Question

$0.2964 \,g$ of copper was deposited on passage of a current of $0.5$ amp for $30$ mins through a solution of copper sulphate. Calculate the oxidation state of $Cu$ (At. mass $63.56$).

• A. $+1$
• B. $+2$
• C. $+3$
• D. $+4$

Answer 1

Answer: (B)

Quantity of charge passed $=0.5 \times 30 \times 60=900$ coulomb
$900$ coulomb will deposit $=0.2964\, g$ of copper
$\therefore 96500$ coulomb will deposit
$=\frac{0.2964}{900} \times 96500=31.75\, g $ of copper
Thus, $31.75$ is the eq. mass of copper
At. mass $=$ Eq. mass $\times$ Valency
$63.56 =31.75 \times x$
$x =+2$