JEE Main202126 Aug 2021Evening ShiftChemistryHydrogenActual
Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Heavy water is used for the study of reaction mechanism. Reason (R): The rate of reaction for the cleavage of O - H bond is slower than that of O - D bond. Choose the most appropriate answer from the options given below :
Options
- ABoth ( A ) and ( R ) are true and ( R ) is the true explanation of ( A ) .
- B( A ) is true but ( R ) is false.
- C( A ) is false but ( R ) is true.
- DBoth ( A ) and ( R ) are true but ( R ) is not the true explanation of ( A ) .
Correct answer
B. ( A ) is true but ( R ) is false.
Step-by-step solution
Statement- 1 : D 2 O is used as a moderator in nuclear reactor and in exchange reactions for the study of reaction mechanisms. Statement- 2   : Bond energy of O - H < Bond energy of O - D . So rate of reaction of cleavage of O-H bond is faster than that of O-D bond.