Question

Assertion :$HCl{O}_4$ is stronger acid than $HCl{O}_3$. Reason: Oxidation state of Cl in $HCl{O}_4$ is $+$VII and in $HCl{O}_3$; it is $+$V.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is B Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

Conjugate base of $HCl{O}_4$ and $HCl{O}_3$ are ${ClO}_4^{-}$ and ${ClO}_3^{-}$ respectively.

Hence the size of ${ClO}_4^{-}$ is bigger tha the size of ${ClO}_3^{-}$ , the stability of ${ClO}_4^{-}$ will be more.

If the conjugate base of an acid is stable , the acid will be stronger (i.e. acid can easily donate proton).

Hence $HCl{O}_4$ is stronger acid than $HCl{O}_3$

So, Assertion is correct and Reason is not the correct explaination of Assertion.

The oxidation state of $Cl$ in $HCl{O}_4$ is

(+1) +( Cl-oxidation state) +(-2 $\times$ 4)=0

Cl-oxidation state= 8-1=7

The Oxidation state of Cl in $HCl{O}_3$ is

(+1)+(Cl-oxidation state )+(-2$\times$ 3)=0

Cl-oxidation state=6-1=5

Hence, reason is correct.