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301. What is the primary function of ATP in the cell?
ⓐ. To store genetic information
ⓑ. To form proteins
ⓒ. To transport oxygen
ⓓ. To provide energy for cellular processes
Correct Answer: To provide energy for cellular processes
Explanation: ATP (adenosine triphosphate) is the main energy carrier in cells. It provides energy for many cellular processes, including muscle contraction, protein synthesis, and active transport across membranes.
302. What is the process by which cells break down glucose to produce ATP called?
ⓐ. Photosynthesis
ⓑ. Cellular respiration
ⓒ. Fermentation
ⓓ. Glycogenesis
Correct Answer: Cellular respiration
Explanation: Cellular respiration is the process by which cells break down glucose (or other organic molecules) to produce ATP. It includes glycolysis, the citric acid cycle, and oxidative phosphorylation.
303. Which of the following processes occurs in the mitochondria and is involved in the production of ATP?
ⓐ. Glycolysis
ⓑ. Calvin cycle
ⓒ. Lactic acid fermentation
ⓓ. Citric acid cycle
Correct Answer: Citric acid cycle
Explanation: The citric acid cycle, also known as the Krebs cycle, occurs in the mitochondria. It produces NADH and FADH2, which are used in the electron transport chain to generate ATP.
304. In photosynthesis, what is the energy source that plants use to produce glucose?
ⓐ. Oxygen
ⓑ. Sunlight
ⓒ. Glucose
ⓓ. Water
Correct Answer: Sunlight
Explanation: During photosynthesis, plants use sunlight as an energy source to produce glucose from carbon dioxide and water. This process occurs in the chloroplasts and involves two stages: the light-dependent reactions and the Calvin cycle.
305. Which of the following is the correct order of stages in cellular respiration?
ⓐ. Glycolysis → Citric acid cycle → Electron transport chain
ⓑ. Citric acid cycle → Glycolysis → Electron transport chain
ⓒ. Glycolysis → Electron transport chain → Citric acid cycle
ⓓ. Electron transport chain → Glycolysis → Citric acid cycle
Correct Answer: Glycolysis → Citric acid cycle → Electron transport chain
Explanation: The correct order of stages in cellular respiration is: first, glycolysis breaks down glucose into pyruvate in the cytoplasm; second, the citric acid cycle occurs in the mitochondria to further break down products; and finally, the electron transport chain produces most of the ATP.
306. What is the role of NADH in cellular respiration?
ⓐ. To donate electrons to the electron transport chain
ⓑ. To produce glucose
ⓒ. To consume oxygen
ⓓ. To break down glucose into pyruvate
Correct Answer: To donate electrons to the electron transport chain
Explanation: NADH is an electron carrier that donates high-energy electrons to the electron transport chain during cellular respiration. This helps generate a proton gradient across the mitochondrial membrane, driving ATP synthesis.
307. In which part of the cell does the citric acid cycle occur?
ⓐ. Cytoplasm
ⓑ. Mitochondrial matrix
ⓒ. Nucleus
ⓓ. Endoplasmic reticulum
Correct Answer: Mitochondrial matrix
Explanation: The citric acid cycle (Krebs cycle) occurs in the mitochondrial matrix, where it processes acetyl-CoA to produce electron carriers (NADH and FADH2) and a small amount of ATP.
308. Which of the following molecules is a product of the electron transport chain?
ⓐ. Oxygen
ⓑ. Glucose
ⓒ. ATP
ⓓ. Pyruvate
Correct Answer: ATP
Explanation: The electron transport chain produces ATP through oxidative phosphorylation. As electrons move along the chain, a proton gradient is created across the mitochondrial membrane, which drives the production of ATP by ATP synthase.
309. What is the net ATP production from one molecule of glucose in glycolysis?
ⓐ. 1 ATP
ⓑ. 2 ATP
ⓒ. 4 ATP
ⓓ. 38 ATP
Correct Answer: 2 ATP
Explanation: Glycolysis, the first stage of cellular respiration, produces a net gain of 2 ATP molecules per molecule of glucose. This occurs by breaking down one molecule of glucose into two molecules of pyruvate, with a small yield of ATP.
310. Which process occurs in the absence of oxygen and results in the production of a small amount of ATP?
ⓐ. Glycolysis
ⓑ. Citric acid cycle
ⓒ. Fermentation
ⓓ. Electron transport chain
Correct Answer: Fermentation
Explanation: In the absence of oxygen, cells undergo fermentation to produce a small amount of ATP. In animals, this results in the production of lactic acid, while in yeast, ethanol and carbon dioxide are produced.
311. What is the primary purpose of the proton gradient in the electron transport chain?
ⓐ. To generate NADH
ⓑ. To produce oxygen
ⓒ. To drive the synthesis of ATP
ⓓ. To break down glucose
Correct Answer: To drive the synthesis of ATP
Explanation: The proton gradient created during the electron transport chain drives the synthesis of ATP through chemiosmosis. The protons flow back into the mitochondrial matrix through ATP synthase, providing the energy required to convert ADP to ATP.
312. What is a galvanic cell?
ⓐ. A device that uses light energy to produce electricity
ⓑ. A device that generates electricity through spontaneous chemical reactions
ⓒ. A device that uses electricity to drive a non-spontaneous chemical reaction
ⓓ. A device used to store electrical energy
Correct Answer: A device that generates electricity through spontaneous chemical reactions
Explanation: A galvanic cell is an electrochemical cell that converts chemical energy from spontaneous redox reactions into electrical energy. It consists of two half-cells, each containing a metal and its ion in solution, connected by a wire and a salt bridge.
313. What is the purpose of a salt bridge in a galvanic cell?
ⓐ. To allow electrons to flow between the half-cells
ⓑ. To prevent the flow of ions between the half-cells
ⓒ. To complete the circuit by allowing ions to flow between the half-cells
ⓓ. To provide energy to the reaction
Correct Answer: To complete the circuit by allowing ions to flow between the half-cells
Explanation: The salt bridge in a galvanic cell completes the electrical circuit by allowing the flow of ions between the half-cells. It prevents charge buildup in the half-cells, maintaining electrical neutrality and allowing the redox reaction to continue.
314. In a galvanic cell, where does oxidation occur?
ⓐ. At the cathode
ⓑ. In the external wire
ⓒ. In the salt bridge
ⓓ. At the anode
Correct Answer: At the anode
Explanation: In a galvanic cell, oxidation occurs at the anode, where electrons are released by the oxidized metal and flow through the external circuit to the cathode. The anode is where the metal loses electrons and goes into solution.
315. In a galvanic cell, where does reduction occur?
ⓐ. At the anode
ⓑ. At the cathode
ⓒ. In the salt bridge
ⓓ. In the external wire
Correct Answer: At the cathode
Explanation: In a galvanic cell, reduction occurs at the cathode, where electrons that have traveled through the external circuit are gained by metal ions in the solution. The metal ions are reduced to solid metal, which plates onto the cathode.
316. What is the standard electrode potential (E°) of a half-cell in a galvanic cell?
ⓐ. The voltage that drives the reaction at the cathode
ⓑ. The voltage of the entire cell
ⓒ. The potential difference between the half-cell and the standard hydrogen electrode
ⓓ. The potential difference between the anode and the cathode
Correct Answer: The potential difference between the half-cell and the standard hydrogen electrode
Explanation: The standard electrode potential (E°) of a half-cell is the potential difference between the half-cell and the standard hydrogen electrode (SHE) under standard conditions. It is used to determine the cell potential and the direction of the redox reaction.
317. What is the purpose of the external wire in a galvanic cell?
ⓐ. To allow the flow of ions between the half-cells
ⓑ. To complete the circuit and allow the flow of electrons between the half-cells
ⓒ. To prevent the oxidation of metal at the anode
ⓓ. To store the electrical energy generated by the cell
Correct Answer: To complete the circuit and allow the flow of electrons between the half-cells
Explanation: The external wire in a galvanic cell connects the two half-cells and allows the flow of electrons between the anode and the cathode. This electron flow generates electrical current, which can be used to do work.
318. What is the overall reaction in a galvanic cell composed of a zinc half-cell and a copper half-cell?
ⓐ. $Zn^{2+} + 2e^- \rightarrow Zn$
ⓑ. $Cu^{2+} + 2e^- \rightarrow Cu$
ⓒ. $Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$
ⓓ. $Zn + 2e^- \rightarrow Cu^{2+}$
Correct Answer: $Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$
Explanation: In a galvanic cell with a zinc half-cell and a copper half-cell, zinc undergoes oxidation at the anode, releasing electrons. Copper ions ($Cu^{2+}$) undergo reduction at the cathode, gaining electrons to form copper metal. The overall reaction is $Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$.
319. Which of the following correctly describes the flow of electrons in a galvanic cell?
ⓐ. From the cathode to the anode
ⓑ. From the anode to the cathode
ⓒ. From the salt bridge to the cathode
ⓓ. From the solution to the external wire
Correct Answer: From the anode to the cathode
Explanation: In a galvanic cell, electrons flow from the anode (where oxidation occurs) to the cathode (where reduction occurs) through the external wire. This flow of electrons generates electric current.
320. What is the function of the anode in a galvanic cell?
ⓐ. To provide electrons to the cathode
ⓑ. To facilitate the reduction of metal ions
ⓒ. To store energy generated by the cell
ⓓ. To prevent oxidation of the cathode
Correct Answer: To provide electrons to the cathode
Explanation: The anode is the site of oxidation, where electrons are released from the metal and flow through the external circuit to the cathode. The anode provides the electrons needed for the reduction process at the cathode.
321. In a galvanic cell, what happens to the metal at the anode?
ⓐ. It is oxidized
ⓑ. It is reduced
ⓒ. It remains unchanged
ⓓ. It gains electrons
Correct Answer: It is oxidized
Explanation: In a galvanic cell, the metal at the anode is oxidized, meaning it loses electrons. These electrons flow through the external circuit to the cathode, where they are used for the reduction of metal ions.
322. What happens to the concentration of ions at the cathode in a galvanic cell?
ⓐ. It increases
ⓑ. It decreases
ⓒ. It remains constant
ⓓ. It depends on the salt bridge
Correct Answer: It decreases
Explanation: At the cathode, metal ions in solution gain electrons and are reduced to form solid metal, causing the concentration of ions in the solution to decrease over time.
323. What is the standard cell potential (E°cell) of a galvanic cell?
ⓐ. The sum of the standard electrode potentials of the anode and cathode
ⓑ. The difference between the oxidation potential of the anode and cathode
ⓒ. The standard potential of the anode only
ⓓ. The potential difference between the two half-cells
Correct Answer: The sum of the standard electrode potentials of the anode and cathode
Explanation: The standard cell potential (E°cell) of a galvanic cell is calculated by summing the standard electrode potentials of the cathode and anode. It gives the overall potential difference between the two half-cells.
324. In a galvanic cell, if the anode is zinc ($Zn$) and the cathode is copper ($Cu$), what happens to the zinc electrode over time?
ⓐ. It gains mass
ⓑ. It loses mass
ⓒ. It remains unchanged
ⓓ. It turns into copper
Correct Answer: It loses mass
Explanation: The zinc electrode undergoes oxidation at the anode, losing electrons and dissolving into the solution as zinc ions ($Zn^{2+}$). Over time, the zinc electrode will lose mass as zinc is oxidized.
325. What happens to the copper electrode in a galvanic cell over time?
ⓐ. It gains mass
ⓑ. It loses mass
ⓒ. It remains unchanged
ⓓ. It dissolves into the solution
Correct Answer: It gains mass
Explanation: At the cathode, copper ions ($Cu^{2+}$) from the solution gain electrons and are reduced to form solid copper metal. As a result, the copper electrode gains mass over time as copper is deposited onto it.
326. What is the function of the salt bridge in a galvanic cell?
ⓐ. To prevent the flow of electrons
ⓑ. To provide a source of oxygen for the reactions
ⓒ. To speed up the redox reactions
ⓓ. To maintain electrical neutrality by allowing the flow of ions
Correct Answer: To maintain electrical neutrality by allowing the flow of ions
Explanation: The salt bridge in a galvanic cell allows the flow of ions between the half-cells to maintain electrical neutrality. It prevents the buildup of charge in each half-cell, ensuring the redox reaction can continue.
327. Which of the following is true about the spontaneous reactions in a galvanic cell?
ⓐ. They require an external power source to proceed
ⓑ. They release energy in the form of electrical current
ⓒ. They absorb energy from the surroundings
ⓓ. They do not involve redox reactions
Correct Answer: They release energy in the form of electrical current
Explanation: In a galvanic cell, the spontaneous redox reactions release energy, which is captured as electrical current. The cell converts chemical energy from the oxidation-reduction process into usable electrical energy.
328. How do redox reactions serve as the basis of cell reactions in a galvanic cell?
ⓐ. By providing electrons for the reduction of ions
ⓑ. By balancing the number of protons in the cell
ⓒ. By facilitating the movement of ions through the salt bridge
ⓓ. By producing oxygen gas
Correct Answer: By providing electrons for the reduction of ions
Explanation: In a galvanic cell, redox reactions provide electrons for the reduction of metal ions at the cathode. The oxidation half-reaction at the anode generates these electrons, which flow through the external circuit, enabling the reduction of ions at the cathode.
329. What happens during the oxidation half-reaction in a redox reaction in a galvanic cell?
ⓐ. Electrons are gained by the metal
ⓑ. Electrons are lost by the metal
ⓒ. Metal ions are formed at the cathode
ⓓ. Oxygen is reduced to form water
Correct Answer: Electrons are lost by the metal
Explanation: During the oxidation half-reaction, the metal at the anode loses electrons, which are then transported through the external circuit to the cathode. This loss of electrons causes the metal to dissolve into its ionized form in the solution.
330. What is the role of electrons in the redox reactions of a galvanic cell?
ⓐ. Electrons are added to both the anode and cathode
ⓑ. Electrons are transferred from the cathode to the anode
ⓒ. Electrons are transferred from the anode to the cathode
ⓓ. Electrons remain in the solution and are not involved in reactions
Correct Answer: Electrons are transferred from the anode to the cathode
Explanation: In a galvanic cell, electrons are transferred from the anode, where oxidation occurs, to the cathode, where reduction occurs. This flow of electrons through the external circuit generates electrical current.
331. Which of the following is true about the reduction half-reaction in a galvanic cell?
ⓐ. Electrons are gained by the metal
ⓑ. Electrons are lost by the metal
ⓒ. The metal dissolves into the solution
ⓓ. Oxygen is oxidized
Correct Answer: Electrons are gained by the metal
Explanation: In the reduction half-reaction, the metal ions in the solution gain electrons at the cathode, forming solid metal. This is the reduction process, where the metal ions are reduced to a lower oxidation state.
332. In the redox reaction $Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$, what is happening to zinc?
ⓐ. Zinc is oxidized
ⓑ. Zinc is reduced
ⓒ. Zinc is neither oxidized nor reduced
ⓓ. Zinc remains in its elemental state
Correct Answer: Zinc is oxidized
Explanation: In this redox reaction, zinc ($Zn$) loses two electrons to become zinc ions ($Zn^{2+}$), which is an oxidation process. The zinc is oxidized, and the electrons flow to the copper ion ($Cu^{2+}$), reducing it to copper metal ($Cu$).
333. In the redox reaction $Cu^{2+} + 2e^- \rightarrow Cu$, what type of reaction is occurring at the cathode?
ⓐ. Oxidation
ⓑ. Combustion
ⓒ. Precipitation
ⓓ. Reduction
Correct Answer: Reduction
Explanation: In this reaction, copper ions ($Cu^{2+}$) gain electrons to form solid copper metal ($Cu$), which is a reduction process. Reduction is the gain of electrons, which occurs at the cathode in a galvanic cell.
334. What does the salt bridge do in a galvanic cell during a redox reaction?
ⓐ. It prevents the flow of electrons
ⓑ. It allows the flow of ions to maintain charge balance
ⓒ. It supplies electrons for oxidation
ⓓ. It provides energy for the redox reaction
Correct Answer: It allows the flow of ions to maintain charge balance
Explanation: The salt bridge allows the flow of ions between the two half-cells of the galvanic cell. It maintains charge balance by preventing the buildup of positive or negative charges in each half-cell, which would otherwise stop the reaction.
335. In a galvanic cell, what happens to the electrons that are released at the anode during oxidation?
ⓐ. They flow into the electrolyte
ⓑ. They are absorbed by the cathode
ⓒ. They flow through the external circuit to the cathode
ⓓ. They stay in the anode and do not move
Correct Answer: They flow through the external circuit to the cathode
Explanation: The electrons released at the anode during the oxidation process flow through the external circuit to the cathode. These electrons are then used in the reduction process at the cathode, completing the redox reaction.
336. How are redox reactions related to the generation of electrical energy in a galvanic cell?
ⓐ. Redox reactions store energy in the form of chemical bonds
ⓑ. Redox reactions transfer energy as heat
ⓒ. Redox reactions generate electrical energy by transferring electrons through the external circuit
ⓓ. Redox reactions are not related to electrical energy generation
Correct Answer: Redox reactions generate electrical energy by transferring electrons through the external circuit
Explanation: Redox reactions in a galvanic cell generate electrical energy by transferring electrons from the anode to the cathode through the external circuit. This flow of electrons constitutes the electrical current that can be used to perform work.
337. Which of the following best describes the function of the anode in a redox reaction in a galvanic cell?
ⓐ. It gains electrons and undergoes reduction
ⓑ. It stores the electrons produced by the cathode
ⓒ. It provides the energy for the reaction
ⓓ. It loses electrons and undergoes oxidation
Correct Answer: It loses electrons and undergoes oxidation
Explanation: The anode in a galvanic cell is the site of oxidation, where the metal loses electrons. These electrons then flow through the external circuit to the cathode, where reduction occurs.
338. What happens to the metal at the cathode in a galvanic cell during a redox reaction?
ⓐ. It is oxidized
ⓑ. It is reduced
ⓒ. It loses electrons
ⓓ. It gains mass and dissolves
Correct Answer: It is reduced
Explanation: At the cathode, metal ions in the solution gain electrons and are reduced to form solid metal. This is the reduction process, and the metal at the cathode gains mass as it plates out from the solution.
339. In the reaction $Zn + Cu^{2+} \rightarrow Zn^{2+} + Cu$, what happens to the copper ions ($Cu^{2+}$)?
ⓐ. They are oxidized to copper metal
ⓑ. They gain electrons and are reduced to copper metal
ⓒ. They remain in solution without any change
ⓓ. They are displaced by zinc
Correct Answer: They gain electrons and are reduced to copper metal
Explanation: In this redox reaction, copper ions ($Cu^{2+}$) gain electrons at the cathode and are reduced to form copper metal ($Cu$), which plates out on the cathode.
340. What is the overall cell potential (E°cell) in a galvanic cell made from zinc and copper half-cells?
ⓐ. Positive, indicating a spontaneous reaction
ⓑ. Negative, indicating a spontaneous reaction
ⓒ. Zero, indicating no reaction occurs
ⓓ. Positive, indicating a non-spontaneous reaction
Correct Answer: Positive, indicating a spontaneous reaction
Explanation: The overall cell potential (E°cell) for a galvanic cell is positive, indicating that the reaction is spontaneous. In a zinc and copper cell, zinc is oxidized and copper is reduced, and this spontaneous redox reaction generates electrical energy.
341. What is the correct representation of a galvanic cell in cell notation?
ⓐ. Anode | Salt bridge | Cathode
ⓑ. Cathode | Anode | Solution
ⓒ. Anode || Cathode
ⓓ. Anode | Solution | Cathode
Correct Answer: Anode | Solution | Cathode
Explanation: In cell notation, the anode is written first, followed by the solution in which the anode is immersed, and then the cathode with its solution. A double vertical line (||) represents the salt bridge or the porous barrier between the two half-cells.
342. In the cell notation for a zinc-copper galvanic cell, which of the following is correct?
ⓐ. $Zn | Zn^{2+} || Cu^{2+} | Cu$
ⓑ. $Cu | Cu^{2+} || Zn^{2+} | Zn$
ⓒ. $Zn | Cu^{2+} || Zn^{2+} | Cu$
ⓓ. $Cu | Zn^{2+} || Cu^{2+} | Zn$
Correct Answer: $Zn | Zn^{2+} || Cu^{2+} | Cu$
Explanation: In the correct cell notation for a zinc-copper galvanic cell, zinc is the anode, and copper is the cathode. The notation $Zn | Zn^{2+} || Cu^{2+} | Cu$ represents the anode (zinc) on the left, the cathode (copper) on the right, with the salt bridge (represented by ||) separating the two half-cells.
343. In the cell notation $Cu | Cu^{2+} || Zn^{2+} | Zn$, which side of the cell is the anode?
ⓐ. The left side (Cu | Cu²⁺)
ⓑ. There is no anode in this cell
ⓒ. The side with the salt bridge
ⓓ. The right side (Zn²⁺ | Zn)
Correct Answer: The right side (Zn²⁺ | Zn)
Explanation: In the given cell notation, the anode is the side where oxidation occurs, which is the zinc half-cell ($Zn | Zn^{2+}$). Oxidation of zinc occurs at the anode, and the copper half-cell ($Cu | Cu^{2+}$) is the cathode.
344. What does the double vertical line (||) in cell notation represent?
ⓐ. The boundary between the two half-cells
ⓑ. The salt bridge or porous barrier between the half-cells
ⓒ. The anode and cathode
ⓓ. The flow of electrons
Correct Answer: The salt bridge or porous barrier between the half-cells
Explanation: The double vertical line (||) in cell notation represents the salt bridge or porous barrier that separates the two half-cells. It allows the flow of ions to maintain electrical neutrality, completing the circuit.
345. In a galvanic cell with the following half-reactions: $Zn \rightarrow Zn^{2+} + 2e^-$ and $Cu^{2+} + 2e^- \rightarrow Cu$, how would you represent this cell in notation?
ⓐ. $Zn | Zn^{2+} || Cu | Cu^{2+}$
ⓑ. $Zn | Zn^{2+} || Cu^{2+} | Cu$
ⓒ. $Cu | Cu^{2+} || Zn^{2+} | Zn$
ⓓ. $Cu | Zn^{2+} || Cu^{2+} | Zn$
Correct Answer: $Zn | Zn^{2+} || Cu^{2+} | Cu$
Explanation: The correct representation of the galvanic cell is $Zn | Zn^{2+} || Cu^{2+} | Cu$, where zinc is the anode (oxidation), and copper is the cathode (reduction). The half-cell reactions are separated by a salt bridge, represented by ||.
346. Which of the following correctly represents a galvanic cell in acidic medium?
ⓐ. $Pb | Pb^{2+} | H^+ || Cu^{2+} | Cu$
ⓑ. $Zn | Zn^{2+} || H^+ | Cu^{2+}$
ⓒ. $Cu | Cu^{2+} || Pb^{2+} | Pb$
ⓓ. $Zn | Zn^{2+} | H^+ || Cu^{2+} | Cu$
Correct Answer: $Zn | Zn^{2+} | H^+ || Cu^{2+} | Cu$
Explanation: The correct representation in acidic medium would involve $Zn | Zn^{2+} | H^+$ as the anode side (where zinc undergoes oxidation) and $Cu^{2+} | Cu$ as the cathode side (where copper ions undergo reduction). The salt bridge is represented by ||.
347. How do you represent a galvanic cell that uses silver and copper in cell notation?
ⓐ. $Ag | Ag^+ || Cu^2+ | Cu$
ⓑ. $Cu | Cu^2+ || Ag^+ | Ag$
ⓒ. $Ag^+ | Ag || Cu | Cu^2+$
ⓓ. $Cu^2+ | Cu || Ag | Ag^+$
Correct Answer: $Ag | Ag^+ || Cu^2+ | Cu$
Explanation: In this cell notation, silver is the anode (where oxidation occurs) and copper is the cathode (where reduction occurs). The salt bridge (||) separates the two half-cells. $Ag | Ag^+ || Cu^2+ | Cu$ correctly represents the silver and copper galvanic cell.
348. What does the single vertical line (|) in cell notation represent?
ⓐ. The flow of electrons
ⓑ. The salt bridge between the half-cells
ⓒ. The phase boundary between different states of matter in a half-cell
ⓓ. The flow of ions in the solution
Correct Answer: The phase boundary between different states of matter in a half-cell
Explanation: The single vertical line (|) in cell notation represents a phase boundary between different states of matter in a half-cell. For example, it separates a solid metal electrode from its ion solution in the half-cell.
349. Which of the following is the correct cell notation for a cell involving the reaction: $Fe \rightarrow Fe^{2+} + 2e^-$ and $Cu^{2+} + 2e^- \rightarrow Cu$?
ⓐ. $Fe | Fe^{2+} || Cu^{2+} | Cu$
ⓑ. $Fe^{2+} | Fe || Cu | Cu^{2+}$
ⓒ. $Cu | Cu^{2+} || Fe^{2+} | Fe$
ⓓ. $Fe | Fe^{2+} || Cu | Cu^{2+}$
Correct Answer: $Fe | Fe^{2+} || Cu^{2+} | Cu$
Explanation: The correct cell notation for this reaction, where iron is oxidized and copper is reduced, is $Fe | Fe^{2+} || Cu^{2+} | Cu$. Iron is the anode (oxidation) and copper is the cathode (reduction).
350. In the cell notation $Ag | Ag^+ || Cu^2+ | Cu$, what does the $Ag^+$ represent?
ⓐ. The solid metal form of silver
ⓑ. The solution of silver ions
ⓒ. The solid copper electrode
ⓓ. The solution of copper ions
Correct Answer: The solution of silver ions
Explanation: In the cell notation $Ag | Ag^+ || Cu^2+ | Cu$, $Ag^+$ represents the solution of silver ions. Silver ($Ag$) is the solid metal electrode in this half-cell, and $Ag^+$ is the ion in solution that participates in the redox reaction.
351. What is the role of the salt bridge in a galvanic cell, as shown in cell notation?
ⓐ. It allows the flow of electrons between the half-cells
ⓑ. It prevents the oxidation of the anode
ⓒ. It maintains electrical neutrality by allowing the flow of ions
ⓓ. It helps in the reduction process at the cathode
Correct Answer: It maintains electrical neutrality by allowing the flow of ions
Explanation: The salt bridge in a galvanic cell maintains electrical neutrality by allowing the flow of ions between the two half-cells. This prevents charge buildup that would otherwise stop the redox reaction from proceeding.
352. Which of the following is represented by the cell notation $Zn | Zn^{2+} || Ag^+ | Ag$?
ⓐ. Zinc is the cathode and silver is the anode
ⓑ. Silver and zinc are both at the cathode
ⓒ. Zinc and silver are both at the anode
ⓓ. Zinc is the anode and silver is the cathode
Correct Answer: Zinc is the anode and silver is the cathode
Explanation: In this cell notation, zinc ($Zn$) is the anode, where oxidation occurs, and silver ($Ag$) is the cathode, where reduction occurs. The double vertical line (||) represents the salt bridge separating the half-cells.
353. What is the standard electrode potential (E°) of a half-cell?
ⓐ. The potential difference between the anode and cathode in a galvanic cell
ⓑ. The potential difference between the half-cell and the standard hydrogen electrode (SHE)
ⓒ. The overall cell potential of the galvanic cell
ⓓ. The amount of energy produced by the cell during a redox reaction
Correct Answer: The potential difference between the half-cell and the standard hydrogen electrode (SHE)
Explanation: The standard electrode potential (E°) of a half-cell is the potential difference between that half-cell and the standard hydrogen electrode (SHE), which is assigned a value of 0.00 V.
354. What is the standard electrode potential of the standard hydrogen electrode (SHE)?
ⓐ. 0.00 V
ⓑ. 1.00 V
ⓒ. -0.00 V
ⓓ. 2.00 V
Correct Answer: 0.00 V
Explanation: The standard electrode potential of the standard hydrogen electrode (SHE) is defined as 0.00 V. The SHE is used as a reference for measuring the electrode potentials of other half-cells.
355. In a galvanic cell, what does a positive standard cell potential (E°cell) indicate?
ⓐ. The reaction is non-spontaneous
ⓑ. No reaction occurs
ⓒ. The reaction is spontaneous
ⓓ. The cell has no net voltage
Correct Answer: The reaction is spontaneous
Explanation: A positive standard cell potential (E°cell) indicates that the redox reaction is spontaneous. In a galvanic cell, the electrons flow from the anode to the cathode, producing electrical energy.
356. What is the standard electrode potential of the copper half-cell ($Cu^{2+} + 2e^- \rightarrow Cu$)?
ⓐ. 0.34 V
ⓑ. 1.10 V
ⓒ. 0.00 V
ⓓ. -0.76 V
Correct Answer: 0.34 V
Explanation: The standard electrode potential of the copper half-cell ($Cu^{2+} + 2e^- \rightarrow Cu$) is 0.34 V. This value is measured relative to the standard hydrogen electrode (SHE), which is assigned a potential of 0.00 V.
357. The EMF of a cell is 1.10 V. What does this indicate about the galvanic cell?
ⓐ. The cell is not working
ⓑ. The reaction is spontaneous and the cell generates 1.10 V of electrical energy
ⓒ. The reaction is non-spontaneous
ⓓ. The cell is neutral and does not generate electrical energy
Correct Answer: The reaction is spontaneous and the cell generates 1.10 V of electrical energy
Explanation: An EMF of 1.10 V indicates that the galvanic cell is generating electrical energy. The positive value suggests that the reaction is spontaneous, and the cell is capable of producing 1.10 V of electrical energy.
358. What is the relationship between standard electrode potentials and the EMF of a cell?
ⓐ. E°cell is the sum of the standard electrode potentials of the cathode and anode
ⓑ. E°cell is the difference between the standard electrode potentials of the anode and cathode
ⓒ. E°cell is the average of the standard electrode potentials of the half-cells
ⓓ. E°cell is always equal to the standard electrode potential of the anode
Correct Answer: E°cell is the difference between the standard electrode potentials of the anode and cathode
Explanation: The standard cell potential (E°cell) is calculated by subtracting the standard electrode potential of the anode from the standard electrode potential of the cathode. It is the driving force for the flow of electrons in the cell.
359. What is the equation used to calculate the EMF of a galvanic cell?
ⓐ. $E°cell = E°cathode – E°anode$
ⓑ. $E°cell = E°anode + E°cathode$
ⓒ. $E°cell = E°cathode + E°anode$
ⓓ. $E°cell = 2E°anode$
Correct Answer: $E°cell = E°cathode – E°anode$
Explanation: The EMF of a galvanic cell is calculated by subtracting the standard electrode potential of the anode (E°anode) from the standard electrode potential of the cathode (E°cathode).
360. If the standard electrode potential of the anode is -0.76 V and the cathode is 0.34 V, what is the standard EMF of the cell?
ⓐ. 0.10 V
ⓑ. -1.10 V
ⓒ. 1.10 V
ⓓ. 0.76 V
Correct Answer: 1.10 V
Explanation: The standard EMF of the cell is calculated by subtracting the standard electrode potential of the anode from that of the cathode:
$E°cell = E°cathode – E°anode = 0.34 V – (-0.76 V) = 1.10 V$.
361. What happens when the EMF of a cell is negative?
ⓐ. The reaction is spontaneous
ⓑ. The reaction is non-spontaneous
ⓒ. The cell will produce energy
ⓓ. The cell is at equilibrium
Correct Answer: The reaction is non-spontaneous
Explanation: When the EMF of a cell is negative, the reaction is non-spontaneous. In such cases, the cell will not generate electrical energy, and the reaction needs external energy to occur (electrolytic cell).
362. What is the standard electrode potential of the standard hydrogen electrode (SHE)?
ⓐ. 0.00 V
ⓑ. 1.00 V
ⓒ. -0.34 V
ⓓ. 2.00 V
Correct Answer: 0.00 V
Explanation: The standard electrode potential of the standard hydrogen electrode (SHE) is defined as 0.00 V. It is used as the reference electrode for measuring the electrode potentials of other half-cells.
363. In a galvanic cell, if the standard electrode potential of the anode is -0.44 V and the cathode is +0.76 V, what is the EMF of the cell?
ⓐ. +1.20 V
ⓑ. +0.32 V
ⓒ. -1.20 V
ⓓ. -0.32 V
Correct Answer: +1.20 V
Explanation: The EMF of the cell is calculated as $E°cell = E°cathode – E°anode = 0.76 V – (-0.44 V) = 1.20 V$. Since the EMF is positive, the reaction is spontaneous.
364. If the standard electrode potential of the cathode is +0.34 V and the anode is -0.76 V, what is the standard EMF of the cell?
ⓐ. -1.10 V
ⓑ. -0.34 V
ⓒ. 0.34 V
ⓓ. 1.10 V
Correct Answer: 1.10 V
Explanation: The standard EMF of the cell is calculated as $E°cell = E°cathode – E°anode = 0.34 V – (-0.76 V) = 1.10 V$. The positive value indicates a spontaneous redox reaction.
365. How does a higher standard electrode potential of a half-cell affect the reaction in a galvanic cell?
ⓐ. It makes the half-cell more easily oxidized
ⓑ. It makes the half-cell more easily reduced
ⓒ. It makes the reaction non-spontaneous
ⓓ. It decreases the cell potential
Correct Answer: It makes the half-cell more easily reduced
Explanation: A higher standard electrode potential of a half-cell indicates that the half-cell is more easily reduced. The substance at the cathode, with the higher potential, gains electrons and undergoes reduction.
366. In the reaction $Zn^{2+} + 2e^- \rightarrow Zn$, what is the standard electrode potential of the half-cell?
ⓐ. +0.76 V
ⓑ. +1.10 V
ⓒ. -0.76 V
ⓓ. -0.44 V
Correct Answer: -0.76 V
Explanation: The standard electrode potential for the half-reaction $Zn^{2+} + 2e^- \rightarrow Zn$ is -0.76 V. This negative value indicates that zinc is more easily oxidized than reduced in this reaction.
367. Which of the following factors does NOT directly affect the electrode potential of a half-cell?
ⓐ. Concentration of ions in solution
ⓑ. Temperature
ⓒ. Pressure
ⓓ. The nature of the electrolyte
Correct Answer: The nature of the electrolyte
Explanation: The electrode potential of a half-cell is influenced by factors such as the concentration of ions in solution, temperature, and pressure. However, the specific nature of the electrolyte does not significantly affect the electrode potential.
368. In the reaction $MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$, what is the oxidation state of manganese before and after the reaction?
ⓐ. $+4$ before, $+2$ after
ⓑ. $+7$ before, $+2$ after
ⓒ. $+6$ before, $+4$ after
ⓓ. $+3$ before, $+2$ after
Correct Answer: $+7$ before, $+2$ after
Explanation: In $MnO_4^-$, Mn is $+7$ (with $4 \times (-2)$ from O and overall $-1$ charge). It becomes $Mn^{2+}$, so Mn is $+2$. The decrease in oxidation state indicates reduction.
369. In the reaction $2Fe^{3+} + 3e^- \rightarrow 2Fe^{2+}$, how do you balance the electrons in a full redox reaction involving both oxidation and reduction half-reactions?
ⓐ. Multiply the reduction half-reaction by $2$ and oxidation half-reaction by $3$
ⓑ. Add $2$ electrons to the oxidation half-reaction
ⓒ. Add $3$ electrons to the reduction half-reaction
ⓓ. No adjustment is necessary
Correct Answer: Multiply the reduction half-reaction by $2$ and oxidation half-reaction by $3$
Explanation: To equate electrons, scale the half-reactions so total electrons lost = gained. A common $LCM$ approach uses factors $2$ and $3$ for $3e^-$ vs $2e^-$ processes.
370. What is the correctly written pair of half-reactions for the redox of hydrogen peroxide by permanganate in acidic medium?
ⓐ. $MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$ and $H_2O_2 \rightarrow O_2 + 2H^+ + 2e^-$
ⓑ. $2MnO_4^- + 16H^+ + 5e^- \rightarrow 2Mn^{2+} + 8H_2O$ and $H_2O_2 \rightarrow O_2 + 2H^+ + 2e^-$
ⓒ. $MnO_4^- + 4H^+ + 3e^- \rightarrow MnO_2 + 2H_2O$ and $H_2O_2 + 2e^- \rightarrow 2OH^-$
ⓓ. $2MnO_4^- + 8H^+ + 5e^- \rightarrow 2Mn^{2+} + 4H_2O$ and $H_2O_2 \rightarrow O_2 + 4H^+ + 2e^-$
Correct Answer: $MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$ and $H_2O_2 \rightarrow O_2 + 2H^+ + 2e^-$
Explanation: In acidic medium, $MnO_4^-$ is reduced to $Mn^{2+}$ (needs $5e^-$) and $H_2O_2$ is oxidized to $O_2$ (produces $2e^-$). These standard forms are then scaled to balance electrons.
371. How do you scale the half-reactions to balance $Cr_2O_7^{2-}$ and $H_2O_2$ in acidic solution?
ⓐ. Multiply the dichromate half-reaction by $1$ and the peroxide half-reaction by $3$
ⓑ. Add electrons to balance the charge in the oxidation half-reaction
ⓒ. Multiply both half-reactions by the same factor
ⓓ. Multiply the dichromate half-reaction by $3$ and the peroxide half-reaction by $2$
Correct Answer: Multiply the dichromate half-reaction by $1$ and the peroxide half-reaction by $3$
Explanation: $Cr_2O_7^{2-} + 14H^+ + 6e^- \rightarrow 2Cr^{3+} + 7H_2O$ consumes $6e^-$. Oxidation $H_2O_2 \rightarrow O_2 + 2H^+ + 2e^-$ produces $2e^-$. Multiply peroxide by $3$ so electrons cancel (overall: $Cr_2O_7^{2-} + 3H_2O_2 + 8H^+ \rightarrow 2Cr^{3+} + 7H_2O + 3O_2$).
372. What is the overall balanced equation for the reaction between hydrogen peroxide and chlorine gas in acidic solution?
ⓐ. $H_2O_2 + 2Cl^- \rightarrow O_2 + 2H^+ + 2Cl^-$
ⓑ. $3H_2O_2 + Cl_2 \rightarrow 2H_2O + O_2 + 2Cl^-$
ⓒ. $H_2O_2 + Cl_2 \rightarrow O_2 + 2H^+ + 2Cl^-$
ⓓ. $2H_2O_2 + Cl_2 \rightarrow O_2 + 2H^+ + 2Cl^-$
Correct Answer: $H_2O_2 + Cl_2 \rightarrow O_2 + 2H^+ + 2Cl^-$
Explanation: In acid, $Cl_2 + 2e^- \rightarrow 2Cl^-$ (reduction) and $H_2O_2 \rightarrow O_2 + 2H^+ + 2e^-$ (oxidation). Adding gives $H_2O_2 + Cl_2 \rightarrow O_2 + 2H^+ + 2Cl^-$.
373. What is the standard electrode potential for the half-reaction $Cl_2 + 2e^- \rightarrow 2Cl^-$?
ⓐ. $+0.76\ \text{V}$
ⓑ. $+1.36\ \text{V}$
ⓒ. $-0.76\ \text{V}$
ⓓ. $+2.00\ \text{V}$
Correct Answer: $+1.36\ \text{V}$
Explanation: The standard reduction potential for $Cl_2/Cl^-$ is $+1.36\ \text{V}$ vs SHE under standard conditions ($1\ \text{M}$, $1\ \text{atm}$, $25^\circ\text{C}$).
374. How do you scale the half-reactions to balance permanganate and oxalate in acidic solution?
ⓐ. Multiply the permanganate half-reaction by $2$ and the oxalate half-reaction by $5$
ⓑ. Multiply the permanganate half-reaction by $5$ and the oxalate half-reaction by $2$
ⓒ. Multiply both half-reactions by the same factor
ⓓ. Add electrons to the oxidation half-reaction
Correct Answer: Multiply the permanganate half-reaction by $2$ and the oxalate half-reaction by $5$
Explanation: $MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$ (needs $5e^-$) and $C_2O_4^{2-} \rightarrow 2CO_2 + 2e^-$ (produces $2e^-$). LCM is $10e^-$, so multiply Mn(VII) reduction by $2$ and oxalate oxidation by $5$.
375. In the reaction between potassium dichromate and hydrogen sulfite ions in acidic solution, what happens to the oxidation state of chromium?
ⓐ. It increases from $+3$ to $+6$
ⓑ. It increases from $+2$ to $+3$
ⓒ. It remains the same
ⓓ. It decreases from $+6$ to $+3$
Correct Answer: It decreases from $+6$ to $+3$
Explanation: Chromium in $Cr_2O_7^{2-}$ is $+6$ and is reduced to $Cr^{3+}$ (decrease by $3$ units per Cr), consistent with dichromate acting as an oxidizing agent.
376. What is the oxidation half-reaction in the reaction between permanganate and oxalate in acidic solution?
ⓐ. $MnO_4^- + 8H^+ + 5e^- \rightarrow Mn^{2+} + 4H_2O$
ⓑ. $2MnO_4^- + 16H^+ + 5e^- \rightarrow 2Mn^{2+} + 8H_2O$
ⓒ. $C_2O_4^{2-} \rightarrow 2CO_2 + 2e^-$
ⓓ. $C_2O_4^{2-} + 2H^+ \rightarrow 2CO_2 + 2e^-$
Correct Answer: $C_2O_4^{2-} \rightarrow 2CO_2 + 2e^-$
Explanation: Oxalate is oxidized to carbon dioxide, releasing $2e^-$. The corresponding reduction is $MnO_4^- \rightarrow Mn^{2+}$ in acid.
You’ve reached Class 11 Chemistry MCQs – Chapter 8: Redox Reactions (Part 4), the final segment of this chapter. This section covers advanced concepts such as electrode potential, electrochemical series, and real-life applications of redox processes in cells and corrosion.
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