Question

Assertion: The photochemical reaction `H_(2) + Cl_(2) rarr 2HCl` and `H_(2) + Br_(2) rarr 2HBr` have equal quantum efficiencies.
Reason: Both the reaction proceed by different mechanism.
A. If both assertion and reason are true and reason is the correct explanation of the assertion.
B. If both assertion and reason are true and reason Iis not the correct explanation of the assertion.
C. If assertion is true but reason is false.
D. If assertion is false but reason is true.

Answer 1

Correct Answer - D
`H_(2) + Cl_(2) rarr 2HCl` has much higher quantum efficiency than `H_(2) + Br_(2) rarr 2HBr`. The first step of secondary process of `H_(2) + Cl_(2) rarr 2HBr` is exothermic while the same for `H_(2) + Br_(2) rarr 2HBr` is endothermic.