Question

A non-stoichiometric compound $Cu_{1 . 8}S$ is formed due to the incorporation of $Cu^{2 +}$ ions in the lattice. What is the mole percentage of $Cu^{2 +}$ present in the compound?

• A. $88.88$
• B. $89.8$
• C. $63.5$
• D. $11.11$

Answer 1

Answer: (D)

In one mole, Let there be $Cu ^{+2}=x$ moles
$\therefore Cu ^{+}=1.8- x$ moles
$\because 2 x +(1.8- x ) 1=+2$
$x =0.2$
$\% Cu ^{+2}=\frac{0.2}{1.8} \times 100=11.11 \%$