Question

The metal which does not react with dilute sulphuric acid is

• A. Aluminium
• B. Zinc
• C. Copper
• D. Iron

Answer 1

The correct option is C

Copper

The correct option is (C) copper.

• When metals react with dilute sulphuric acid they produce the corresponding salt and Hydrogen gas $\left({\mathrm{H}}_2\right)$.
• In this reaction the metal replaces hydrogen from the acid, to release hydrogen gas. It is a type of displacement reaction.
• Displacement reaction is the reaction in which a highly reactive metal replaces a less reactive metal from its salt.
• The reactivity series of metals is:

$$\begin{gathered} \mathrm{K},\mathrm{Na},\mathrm{Ca},\mathrm{Mg},\mathrm{Al},\mathrm{Zn},\mathrm{Fe},\mathrm{Sn},\mathrm{Pb},\mathrm{H},\mathrm{Cu},\mathrm{Hg},\mathrm{Ag},\mathrm{Au}. \\ \stackrel{\mathrm{Decreasing}\mathrm{order}\mathrm{of}\mathrm{reactivity}}{\to } \end{gathered}$$

• As we can see, Copper $\left(\mathrm{Cu}\right)$ is less reactive than Hydrogen $\left(\mathrm{H}\right)$, hence, Copper cannot displace Hydrogen from Sulphuric acid $\left({\mathrm{H}}_2{\mathrm{SO}}_4\right)$.
• While Aluminium, Zinc and Iron are more reactive than Hydrogen, so, they can replace hydrogen from acids to produce the salt and hydrogen gas. Hence these metals react with sulphuric acid.