Question

Copper dissolves in $HN{O}_3$, but not in $HCl$. Why?

Answer 1

Dissolution of a metal in $HCl$ actually means that the metal has displaced $H^{+}$ ions and form its own salt. However, copper is unable to displace $H$ sine copper lies below $H$ in electropositive character series. $HN{O}_3$ is a strong oxidising agent also. Hence it rather oxidises copper to ${Cu}^{2+}$ ions and hence copper dissolves in $HN{O}_3$.