Verified Solution • 2025–26 Session moderate

QJEEM23Ch47d6: JEE Main 2023 Chemistry - Class 11 JEEM23Ch47d6 Solution: Given below are two statements, one is labelled as Assertion A…

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Isotopes of hydrogen have almost same chemical properties, but difference in their rates of reaction.

Reason R : Isotopes of hydrogen have different enthalpy of bond dissociation.

In the light of the above statements, choose the most appropriate answer from the options given below:

Multiple Choice Options

  • A A is not correct but R is correct
  • B Both A and R are correct but R is NOT the correct explanation of A
  • C A is correct but R is not correct
  • D Both A and R are correct and R is the correct explanation of A

Step-by-Step Verified Solution

Assertion A : Isotopes of hydrogen (protium, deuterium, and tritium) have almost the same chemical properties because they have the same number of protons and electrons, which dictate chemical behavior. However, they differ in their rates of reaction due to differences in their atomic masses, which affect reaction kinetics.

Reason R : The isotopes of hydrogen have different enthalpy of bond dissociation due to their differences in atomic mass. The stronger bond in deuterium compared to protium, for example, leads to higher bond dissociation enthalpy. This, in turn, influences the rate of reactions involving these isotopes, as breaking the bonds requires different amounts of energy.

Therefore, the correct answer is Both A and R are correct, and R is the correct explanation of A.

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