Question

A constant current of $30A$ is passed through an aqueous solution of $NaCl$ for a time of $1.00h$. What is the volume of ${Cl}_2$ gas at STP produced?

• A. $30.00L$
• B. $25.08L$
• C. $12.54L$
• D. $1.12L$

Answer 1

The correct option is C $12.54L$

$2NaCl\stackrel{Electrolysis}{\to }2N{a}^{+}+2C{l}^{-}$

At anode: $2C{l}^{-}\to C{l}_2+2e^{-}$

At cathode: $2N{a}^{+}+2e^{-}\to 2Na.$

So 2 Faraday of electricity is required to liberate 1 mole $=22.4$ litres of $C{l}_2$ at $STP$.

Amount of current passed $=30\times 60\times 60=108000coulombs.$

So 108000 coulombs will liberate $=\frac{108000}{(96500\times 2)}=0.5596$ moles $C{l}_2$.

No.of litres of chlorine liberated at STP $=0.5596\times 22.4=12.54litres.$

Hence, option C is correct.