Question

$A{g}_{2}S+NaCN\to A$

$A+Zn\to B$
$B$ is a metal. Hence, $A$ and $B$ are respectively:

• A. $N{a}_2\left[Zn\right(CN{)}_4],Zn$
• B. $Na\left[Ag\right(CN{)}_2],Ag$
• C. $Na\left[Ag\right(CN{)}_4],Ag$
• D. $N{a}_3\left[Ag\right(CN{)}_4],Ag$

Answer 1

Answer: (B)

$Na\left[Ag\right(CN{)}_2],Ag$

Reactions occurs in extraction of silver.

$A{g}_{2}S+4NaCN\to 2Na\left[Ag\right(CN{)}_2]+N{a}_{2}S$ (reversible reaction)

$4N{a}_{2}S+5O_2+H_{2}O\to 2N{a}_{2}S{O}_4+4NaOH+2S$

and $\underset{A}{2Na\left[Ag\right(CN{)}_2]}+Zn\to N{a}_2\left[Zn\right(CN{)}_4]+\underset{B}{2Ag}$
Option B is correct.