Q14 / 160 · AP EAMCET 2023 (19 May Shift 1) · Chemistry

Given below are two statements Assertion (A): Protium and deuterium differ in their rates of reactions. Reason (R): They have different enthalpies of bond dissociation. The correct answer is

  • Correct answer
    A
    Both (A) and (R) are correct and, (R) is the correct explanation of $(A)$
  • B
    Both (A) and (R) are correct but (R) is not the correct explanation of $(\mathrm{A})$
  • C
    (A) is correct but (R) is incorrect
  • D
    (A) is incorrect but (R) is correct

Solution

$\mathrm{H}-\mathrm{H}$ bond enthalpy $=435.88 \mathrm{~kJ} \mathrm{~mol}^{-1}$ $\mathrm{D}-\mathrm{D}$ bond enthalpy $=443.35 \mathrm{~kJ} \mathrm{~mol}^{-1}$. Due to a difference in their bond dissociation enthalpies, they undergo chemical reactions at different rates. Thus, both, (A) and (R) are true and (R) correctly explains (A).

Hence, the correct answer is option: 'A'.

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