Question

In which of the following cases a chemical reaction is possible ?

• A. $ZnS{O}_{4(aq)}$ is placed in a copper vessel
• B. $AgN{O}_3$ solution is stirred with a copper spoon
• C. Conc. $HN{O}_3$ is stored in a platinum vessel
• D. gold ornaments are washed with dil $HCl$

Answer 1

Answer: (B)

Platinum and gold lie at the bottom of the reactivity series. Thus it does not react with $HN{O}_3$ and $HCl$. Again, $Zn$ is more reactive than copper. Thus, copper will be displaced by $Zn$, if $ZnS{O}_4$ is placed in a copper vessel. But $A{g}^{+}$ is less reactive than copper. Thus, copper will displace silver. The corresponding reaction is:

$2AgN{O}_3+Cu\to Cu{\left(N{O}_3\right)}_2+2Ag$