Question

A solution of CuSO₄ is electrolysed using a current of 1.5 amperes for 10 minutes. What mass of Cu is deposited at cathode? [Atomic mass of Cu = 63.7]

Options

• 0.637 g

• 0.297 g

• 0.150 g

• 0.395 g

Answer 1

0.297 g

Explanation:

Given, current (i)= 1.5 A

Time (t) = 10 min

Quantity of electricity passed will be,

Q = it

= 1.5A × 10 × 60 s

= 900 C

Electrolysis of CuSO₄ gives

\[\ce{Cu^{2+} + 2e- -> Cu}\](atomic mass of Cu = 63.7)

Therefore, electricity required for 1 mole,

i.e. 63.7 g Cu is 2F = 2 × 96500 C

∴ 2 × 96500 C deposit Cu = 63.7 g

∴ 900 C will deposit Cu = `(63.7 xx 900)/(2 xx 96500)`g

= 0.297 g