All Free Chemistry MCQs with Answers

• A. The flow of electrons takes place from copper to zinc
• B. Eoredof copper electrode is less than that of zinc electrode
• C. Zinc acts as an anode and copper as cathode
• D. All are correct

Explanation: Anode: The electrode where oxidation occurs (loss of electrons). Zinc is more readily oxidized than copper, meaning it loses electrons…

• A. IM ZnO solution
• B. 1M ZnSO4 solution
• C. I.5M ZnSO4 solution
• D. 0.IM ZnSO4 solution

Explanation: Standard electrode potential is measured in a half-cell containing the metal (Zn) in contact with a solution of its ions (ZnSO4) at 1M…

• A. Electrons
• B. Current
• C. anions
• D. ions

Explanation: While some anions might migrate through the salt bridge, a mixture of cation and anion movement is necessary for proper circuit completion.

• A. by addition of fresh solution
• B. replacing external circuit with external source of electricity
• C. by removal of solution
• D. by heating it

Explanation: Voltaic cells, also known as galvanic cells, convert chemical energy into electrical energy.

• A. to form positive ions
• B. to form negative tons
• C. gain electrons
• D. all are possible

Explanation: A higher standard reduction potential indicates a greater tendency for a species to gain electrons and be reduced.

• A. rechargeable
• B. Non-rechargeable
• C. Electrolytic cells
• D. Daniel cell

Explanation: Secondary cells, also known as rechargeable batteries, can be restored to their original state by reversing the discharge process through…

• A. 1.5 volts
• B. 2 volts
• C. 3 volts
• D. 1 volt

Explanation: The capacity of a lead accumulator cell can be expressed in both Ampere-hours (Ah) or Watt-hours (Wh) and volts,depending on the context.

• A. MnO₂
• B. Zn (Zinc)
• C. AgO₂ (Silver oxide)
• D. Cadmium

Explanation: Anode vs Cathode: In a battery, the anode is the negative electrode where oxidation occurs (loss of electrons).

• A. Gain of electrons
• B. Loss of electrons
• C. Gain of hydrogen
• D. Addition of electrons

Explanation: Oxidation = loss of electrons (OIL). Reduction = gain of electrons (RIG).

• A. Sodium
• B. Magnesium
• C. Aluminum
• D. lron

Explanation: Option A) Sodium is not obtained by electrolysis of fused bauxite. Sodium is usually obtained by the electrolysis of molten sodium…

• A. Bromine is reduced and water is oxidized.
• B. Bromine is both reduced and oxidized.
• C. Bromine is oxidized and carbonate is reduced.
• D. Bromine is neither reduced nor oxidized.

Explanation: The correct answer is that bromine is both reduced and oxidized. This reaction is an example of a disproportionation reaction.

• A. Oxidation-Reduction (Redox) Reaction
• B. Addition Reaction
• C. Substitution Reaction
• D. Autoxidation Reaction
• E. Reduction Reaction

Explanation: The correct answer is a substitution reaction. In the reaction CH3Cl + Cl2 → CH2Cl2 + HCl, a chlorine atom substitutes a hydrogen atom in…

• A. Electrons on the left-hand side only.
• B. Electrons on the right-hand side only.
• C. Electrons on Either the left or right-hand side.
• D. None of these.

Explanation: In the ion-electron method, each half-reaction is balanced by ensuring that the number of electrons is the same on both sides of the…

• A. 2 atm
• B. 780 mmHg
• C. 19 Psi
• D. 1 atm

Explanation: When hydrogen gas bubbles into a one molar solution of HCl, it is usually assumed to be at standard conditions unless otherwise specified.

• A. Copper Sulfate
• B. Copper Chloride
• C. Zinc Chloride
• D. Zinc Sulfate

Explanation: In a voltaic cell, the zinc electrode is typically immersed in a zinc sulfate (ZnSO4) solution, which serves as the electrolyte.

• A. Potential energy
• B. Chemical energy
• C. Kinetic energy
• D. Free Electrons

Explanation: A voltaic cell produces electrical energy from chemical energy. This type of electrochemical cell utilizes spontaneous redox reactions to…

• A. Spontaneous reactions
• B. Oxidation-reduction reaction
• C. Reduction reaction
• D. Oxidation reaction

Explanation: Electrolysis is a process where an electric current is passed through a substance to effect a chemical change.

• A. E
• B. E-1
• C. E°
• D. A

Explanation: The standard electrode potential, denoted by 'E°', represents the potential of an electrode reaction under standard conditions, which…

• A. Balance out all the Reactants
• B. Write the skeleton Equation
• C. Calculate the oxidation number
• D. Identify the elements

Explanation: b) Write the skeleton Equation: This option is a correct step in balancing a redox equation.

• A. NaCl + AgNO3 → NaNO3 + AgCl
• B. 2Cl- → Cl2 + 2e-
• C. 2Na + Cl2 → 2NaCl
• D. Na + 1e- → Na

Explanation: The oxidation number of sodium increases from 0 (on the reactants side) to +1 (on the products side), hence sodium is being oxidised.