Question

Which of the following statement is correct?

• A. $H_{2}S{O}_3$ is less
  acidic than $H_{2}S{O}_4$
• B. $HN{O}_3$ is less acidic than $HN{O}_2$
• C. $S{O}_2\left(g\right)$ is reduced in the atmosphere during thunderstrom.
• D. $C{O}_2$ gas develop more acidity in rain water than $S{O}_2$

Answer 1

The correct option is A $H_{2}S{O}_3$ is less

acidic than $H_{2}S{O}_4$
Sulphurous acid $H_{2}S{O}_3$ is less acidic than sulphuric acid $H_{2}S{O}_4$. When a proton is lost by sulphurous acid, the negative charge is delocalized on 3 O atoms and when a proton is lost by sulphuric acid, the negative charge is delocalized by 4 O atoms. Since the extent of delocalization in $HS{O}_3^{-}$ ion is less than the extent of delocalization in $HS{O}_4^{-}$, the stability of anion and the acidity of the acid in sulphurous acid is lower than in sulphuric acid.