In lead chamber process, a mixture containing $SO _{2}$, air NO is treated with steam $\left( H _{2} O \right)$.
In this reaction, NO (nitric oxide) act as a catalyst.
$2 SO _{2}+\underset{\text { (From air) }}{ O _{2}}+2 H _{2} O +\underset{\text { Catalyst }}{[ NO ]} \to 2 H _{2} SO _{4}+\underset{\text { Catalyst }}{[ NO ]}$
P block elements are those in which the last electron enters any of the three p-orbitals of their respective shells. Since a p-subshell has three degenerate p-orbitals each of which can accommodate two electrons, therefore in all there are six groups of p-block elements.
P block elements are shiny and usually a good conductor of electricity and heat as they have a tendency to lose an electron. You will find some amazing properties of elements in a P-block element like gallium. It’s a metal that can melt in the palm of your hand. Silicon is also one of the most important metalloids of the p-block group as it is an important component of glass.