Free Electrochemistry MCQs with Answers
696 Electrochemistry MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Electrochemistry describes electron transfer through oxidation and reduction, identifies oxidizing and reducing agents, and applies oxidation numbers to balance redox equations. It also covers electrode potential and the standard hydrogen electrode, which provides the reference for comparing the reduction tendencies of other electrodes.
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Read the Electrochemistry notesFree MDCAT chapter notes with key terms696 questions · page 14 of 35
- A. Possibility of reaction to take place
- B. Extent of a reaction
- C. Direction of reaction
- D. All of these
Explanation: The electrochemical series can predict the direction of a reaction, the extent of a reaction, and whether a reaction will take place or…
Correct answer: All of these- A. Light
- B. Ni catalyst
- C. Pd catalyst
- D. Pt catalyst
Explanation: Platinum is used as a catalyst in the reaction between H2 and O2 which increases the rate of reaction between the two by adsorbing both…
Correct answer: Pt catalyst- A. Electrons lost are less than electrons gained
- B. Electrons lost are more than electrons gained
- C. Electrons lost are equal to electrons gained
- D. None of these
Explanation: The basic principle used when balancing the equation by oxidation number is that electrons lost are equal to electrons gained.
Correct answer: Electrons lost are equal to electrons gained- A. None of these
- B. Reaction is exothermic
- C. Reaction is non-spontaneous
- D. Reaction is spontaneous
Explanation: The voltage value for a reaction is given by: E° = E° cathode - E° anode where E° is the cell voltage value for a reaction.
Correct answer: Reaction is non-spontaneous- A. Indicator of electrochemical cell
- B. Indicator of salt bridge
- C. Indicator of SHE
- D. Indicator of electrode potential
Explanation: In the representation of redox reactions that occur in an electrochemical cell, the symbol, || , represents the salt bridge.
Correct answer: Indicator of salt bridge- A. Voltmeter
- B. Potentiometer
- C. Ammeter
- D. Galvanometer
Explanation: Electrode potentials are measured by voltmeters.
Correct answer: Voltmeter- A. Cu can oxidize Zn
- B. Cu can not oxidize Zn
- C. Reaction is nonspontaneous
- D. Zn can oxidize Cu
Explanation: From the reaction, we can observe that the oxidation state of Zn increases, meaning Zn is oxidized.
Correct answer: Cu can oxidize Zn- A. Act as an oxidizing agent
- B. Easily be reduced
- C. Easily be oxidized
- D. Easily gain electrons
Explanation: Reduction potential is the measure of the tendency of an element to gain electrons and be reduced.
Correct answer: Easily be oxidized- A. 1.1
- B. 1.76
- C. 1
- D. 0
Explanation: The electrode potential of a standard hydrogen electrode or SHE is taken as a reference to which the electrode potentials of other…
Correct answer: 0- A. Feasibility of reaction
- B. Mechanism of reaction
- C. Type of reaction
- D. Order of reaction
Explanation: The EMF series helps determine the feasibility of a reaction. Any element higher up in the series can reduce or displace the one lower in…
Correct answer: Feasibility of reaction- A. Fe is reduced
- B. Cl is oxidized
- C. Fe is oxidized
- D. Oxidation state of Cl changes from 0 to +4
Explanation: In the given reaction: Fe is oxidized. Its oxidation state changes from 0 to +3. Cl is reduced. Its oxidation state changes from 0 to -1.
Correct answer: Fe is oxidized- A. KCl solution
- B. MgCl₂ solution
- C. NaCl solution
- D. K₂SO₄ solution
Explanation: A Salt bridge is a connection between the two half-cells of a galvanic cell.
Correct answer: KCl solution- A. 6
- B. 5
- C. 7
- D. 4
Explanation: Following are the oxidation numbers: K = 1 O = -2 Cr =? In K₂CrO₄: (+1)2 + x + (-2)4 = 0 +2 + x - 8 = 0 x - 6 = 0 x = +6 Hence the…
Correct answer: 6- A. Pass the electric current
- B. Mix solution of two half-cells
- C. Prevent the flow of ions
- D. Allow movement of ions between two half-cells
Explanation: A salt bridge is used to connect the oxidation and reduction half-cells of a galvanic cell (voltaic cell), a type of electrochemical cell.
Correct answer: Allow movement of ions between two half-cells- A. It describes the tendency of an atom to lose electrons
- B. It describes the electronegativity of an atom
- C. It describes the tendency of atoms to gain and lose electrons
- D. It describes the tendency of an atom to gain electrons
Explanation: An increase in the Oxidation State means a loss of electrons. A decrease in the oxidation state means a gain of electrons.
Correct answer: It describes the tendency of atoms to gain and lose electrons276. Electrons flow from:
- A. None of these
- B. Both of these
- C. Cathode to anode
- D. Anode to cathode
Explanation: The direction of electrons in the external circuit is from the anode to the cathode.
Correct answer: Anode to cathode- A. Will produce hydrogen with dilute acids
- B. Will form a salt with acid
- C. None of these
- D. Will not produce hydrogen with dilute acids
Explanation: The arrangement of elements in order of increasing reduction potential values is called electrochemical series.
Correct answer: Will not produce hydrogen with dilute acids- A. Nature of reaction
- B. Temperature of reaction
- C. None of these
- D. Pressure of reaction
Explanation: During electrolysis, when electric current flows through the circuit, the electrodes gain or lose electrons.
Correct answer: Nature of reaction- A. Free charge from zinc sulfate solution
- B. Electrons
- C. Protons
- D. Zinc ions
Explanation: In a galvanic cell, copper loses electrons to form copper ions, giving the copper compartments a negative charge.
Correct answer: Electrons- A. 3m/4
- B. 3m/5
- C. 5m/6
- D. m/4
Explanation: FAs can be seen from the above reaction,The equivalent weight of this reaction can be calculated as molecular mass divided by n…
Correct answer: 3m/4