Question

Assertion :$KI{O}_3$ reacts with $KI$ to liberate iodine which is titrated with standard hypo solution. The reactions are:
(i) $I{O}_3^{-}\to I_2$ (Valency factor = 5/3)
(ii) $I_2+S_2{O}_3^2\to S_4{O}_6^{2-}+I^{-}$ (Valence factor $=$2)
Milliequivalent of hypo$=$ meq. of $I_2=$meq. of $I{O}_3^{-}$.

Milliequivalent of hypo = $2\times meq.$ of $I{O}_3^{-}=$ meq. of $I^{-}$.

Reason: Valency factor of $I_2$ in both the equation are different, therefore we cannot compare milliequivalents in sequence.

• 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 incorrect but Reason is correct
• D. Both Assertion and Reason are correct

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Milliequivalent of $I{O}_3^{-}$ is equal to milliequivalent of $I^{-}$.
Milliequivalent of hypo is equal to milliequivalent of $I{O}_3^{-}$ plus milliequivalent of $I^{-}$.
The milliequivalent of hypo is twice the milliequivalent of $I{O}_3^{-}$. It is also twice the milliequivalent of $I^{-}$.