Question

How many atoms of calcium will be deposited from a solution of $CaCl _{2}$ by a current of $25\, mA$ flowing for $60 $ seconds?

• A. $4.68 \times 10^{18}$
• B. $4.68 \times 10^{15}$
• C. $4.68 \times 10^{12}$
• D. $4.68 \times 10^{9}$

Answer 1

Answer: (A)

Quantity of electricity passed $=\frac{25}{1000} \times 60=1.5 \,C$

$2 F =2 \times 96500 \,C$ will deposit $1\, mole\, Ca$

$ \therefore 1.5 \,C \text { will deposit } Ca =\left(\frac{1}{2 \times 96500} \times 1.5\right) mole $

$=\frac{1}{2 \times 96500} \times 1.5 \times 6.023 \times 10^{23} \text { atom }=4.68 \times 10^{18} $