Statement I: When $\mathrm{PbO}_{2}$ reacts with a dilute acid, it gives hydrogen peroxide.
Statemen

Question

Statement I: When $\mathrm{PbO}_{2}$ reacts with a dilute acid, it gives hydrogen peroxide.
Statement II: Graphite is used as a solid lubricant.

Professor PC Thomas Classes · Answer

(I)-False, $\mathrm{PbO}_{2}$ is a dioxide. It does not give $\mathrm{H}_{2} \mathrm{O}_{2}$ on reaction with dilute acid. It reacts as follows :\ $\mathrm{PbO}_{2}+\underset{	ext { (dil.) }}{4 \mathrm{HCl}} \longrightarrow \mathrm{PbCl}_{2}+\mathrm{Cl}_{2}+2 \mathrm{H}_{2} \mathrm{O}$\ 
(II)-Graphite has a two dimensional sheet structure and in it the carbon atoms are $s p^{2}$ hybridised. These layers of carbon atoms are held together by weak van der Waals' forces and so they can easily slip over one another and this imparts lubricating properties to graphite.\