Question

Which of the following statement is true for all voltaic (or galvanic) cells? 

(I) Reduction occurs at the cathode. 

(II) The anode gains mass during discharge (note: this means operation of the cell.) 

(III) The voltage is less than or equal to zero. 

(a) Only III 

(b) Only I 

(c) Only II 

(d) II and III 

(e) I, II, and III

Answer 1

12.) The only statement that is true for all voltaic (or galvanic) cells as given in the question is (I) Reduction occurs at the cathode. where an species from aqueous solution takes up electron and gets deposited at the cathode which is the fundamental theory in an electrochemical reaction as follows: Z⁺(aq)+ e^- ----> Z(s)

Hence the correct answer to this question is option (b) only (I) [Reduction occurs at the cathode.]

Statement (II) The anode gains mass during discarge is wrong statement it is because at anode oxidation takes place which means electrons pass out to the solution in a electrochemical cell i.e. it corrodes the electrode or electrode experiences mass loss.

Statement (III)The voltage is less than or equal to zero. is also a wrong statement because the voltage may also be positive / greater yhan zero which actually depends upon the species used in the electrochemical recation.

Answer 2

The answer is c. Only 1