Multiple choice

Assertion: All four C-H bonds in CH4 molecule do not possess the same bond energy. Reason: The bond dissociation energies are usually the average values.

Directions: In each of the questions given below, there are two statements labelled as Assertion (A) and Reason (R). Mark your answer as per the codes provided below:
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true but R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.
E. Both A and R are false.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is not the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because CH4 contains 4 identical C-H bonds and it seems reasonable that they should have the same (theoretically) bond energy but not same (practically) bond energy. However, if you took CH4 into pieces, one hydrogen at a time, it needs a different amount of energy to break each of the 4 C-H bonds. Every times you break hydrogen off a carbon, the environment of those left behind changes and the strength of the bond is affected by what else is around it. In this case, the bond energy is quoted as average values.

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