Question

10. The masses of different substances liberated in electrolysis by the same quantity of electricity are proportional to their relative a) atomic masses b) valencies c) ratios of atomic masses and valency d) product of atomic masses and valency.​

Answer 1

Answer:

c explanation is in the image

Answer 2

The masses of different substances liberated in electrolysis by the same quantity of electricity are proportional to their relative ..

1. atomic masses
2. valencies
3. ratios of atomic masses and valencies
4. products of atomic masses and valencies

answer : ratios of atomic masses and valencies.

explanation : let an element M of valency x is liberated in electrolysis after supplying current I for t time.

  deposition of element M at cathode,

                                              $M^{x+}+xe^{-1}$ ⇄ M

it is clear that to deposit one mole of M, x moles of electrons are needed.

and we know, 1 mole of electrons is equivalent to 96500 C.

charge , q = current × time = I × t

so, no of moles of electrons is equivalent to q C = I × t/96500

so the no of moles of M deposited at cathode = I × t/(96500 × x)

now the mass of element M deposited at cathode = I × t × W/(96500 × x)

                                                                            = (It/96500) × (W/x)

where W is atomic mass.

here it is clear that the mass of different substance liberated in electrolysis by the same quantity of electricity is proportional to its ratio of atomic and valency. hence, option (c) is correct.