Question

Select correct answer:

(I)$KF$ combines with $HF$ to form $KH{F}_2$. The compound contains the species:
(a)$K^{+},F^{-}$ and $H^{+}$
(b)$K^{+},F$ and $HF$
(c)$K^{+}$ and $[H{F}_2{]}^{-}$
(d)$[KHF{]}^{+}$ and $F^{-}$

(II) Which compound is formed when excess of $KCN$ is added to aqueous solution of copper sulphate?
(a)$Cu(CN{)}_2$
(b)$K_2\left[Cu\right(CN{)}_4]$
(c)$K\left[Cu\right(CN{)}_2]$
(d)$K_3\left[Cu\right(CN{)}_4]$

• A. (I)$\left(a\right)$ (II)$\left(a\right)$
• B. (I)$\left(b\right)$ (II)$\left(c\right)$
• C. (I)$\left(c\right)$ (II)$\left(d\right)$
• D. (I)$\left(d\right)$ (II)$\left(b\right)$

Answer 1

The correct option is C (I)$\left(c\right)$ (II)$\left(d\right)$

(I)$KF$ combines with $HF$ to form $KH{F}_2$. The compound contains the species:

$KF+HF\to KH{F}_2$.

The compound $KH{F}_2$ contains the species: $K^{+}$ and $[H{F}_2{]}^{-}$.

(II) when excess of $KCN$ is added to aqueous solution of copper sulphate $K_3\left[Cu\right(CN{)}_4]$ is formed.

Hence option option C is correct.