Question

A copper coin was dipped in silver nitrate solution for a few hours/days. What will happen to the copper coin? What will happen to the color of the solution?

Answer 1

Hint: The reactivity of a metal is its ability to displace any other metal from its salt solution. A reactivity series is implemented that tells the reactivity of metals. The series has highly reactive metals at the top and less reactive metals at the bottom. The metals at the top can displace metals at the bottom from their aqueous salt solutions.

Complete answer:
Metals are highly reactive substances that consist of the s and the d block of the periodic table. The varying reactivity of metals can be depicted by the activity series in which the highly reactive metals are at the top and the least reactive metals at the bottom.
We have been given a copper coin dipped in silver nitrate solution for a few hours to days. In the reactivity series copper is above the least reactive metals, while silver is a noble metal and at the bottom of this series. Therefore copper replaces silver in its aqueous salt solution. So, the copper coin will have a grayish silver deposit on it. The color of the solution will change into blue due to the copper.
The reaction is: $Cu+2AgN{{O}_{3}}\to Cu{{(N{{O}_{3}})}_{2}}+Ag$
Hence, copper displaces silver and the copper coin has grey deposit, while the solution turns blue in color.

Note:
The metals like noble metals, gold, silver and platinum are least reactive and are at the bottom of the activity series. A more reactive metal displaces a less reactive metal from its aqueous salt solution. This means if we add a silver coin to copper nitrate solution then no change will occur as silver will not displace copper.