Question

Assertion :${Cl}_2$ or ${Br}_2$ changes $KI$ into $I_2$(violet in ${CCl}_4$ layer), ${Cl}_2$ changes $KBr$ into ${Br}_2$(orange-yellow in ${CCl}_4$ layer). Thus, ${Cl}_2$ would change mixture of $KIandKBr$ into violet layer in ${CCl}_4$. Reason: Oxidising power is in order $I_2<{Br}_2<{Cl}_2<F_2$.

• 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. Assertion is incorrect but Reason is correct.

Answer 1

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

The increasing order of the oxidizing power is $I_2<{Br}_2<{Cl}_2<F_2$.

${Cl}_2$ oxidises ${Br}^{-}$ to ${Br}_2$, and ${Br}_2$ oxidises $I^{-}$ to $I_2$(violet)

Thus chlorine and bromine can displace iodine from KI. This gives violet colour to carbon tetrachloride layer.

Similarly chlorine can displace bromine from KBr. This gives orange yellow colour to carbon tetrachloride layer.

Thus chlorine can change the mixture of KI and KBr into violet layer in carbon tetrachloride.

Thus, both Assertion and Reason are correct and Reason is the correct explanation for Assertion.