Question

Electrolysis of dilute aqueous NaCl solution was carried out by passing 10 mA current. The time required to liberate 0.01 moles of $H_2$ gas at the cathode is

• A. $9.65\times {10}^{4}s$
• B. $19.3\times {10}^{4}s$
• C. $28.95\times {10}^{4}s$
• D. $38.6\times {10}^{4}s$

Answer 1

The correct option is B $19.3\times {10}^{4}s$

0.01 moles of $H_2$ will require $2\times 0.01=0.02$ moles of electrons or $0.02$ faradays.

$\frac{I\left(A\right)\times t\left(s\right)}{96500}=0.02$

$\frac{\frac{10mA}{1000mA/A}\times t\left(s\right)}{96500}=0.02$

$t=19.3\times {10}^4$ s

Hence, the corret option is $B$