Question

Given below are two statements : One is labelled as Assertion A and other is labelled as Reason R.

Assertion A : The dihedral angles in $H_2{O}_2$ in gaseous phase is ${90.2}^{\circ }$ and in solid phase is ${111.5}^{\circ }$.
Reason R : The change in dihedral angle in solid and gaseous phase is due to the difference in the inter molecular forces.

Choose the most appropriate answer from the options given below for A and R.

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

Answer 1

The correct option is C A is not correct but R is correct.

(a) $H_2{O}_2$ structure in gas phase, dihedral angle is ${111.5}^{\circ }$.
(b) $H_2{O}_2$ structure in solid phase at $110K$, dihedral angle is ${90.2}^{\circ }$.


The change in dihedral angle in solid and gaseous phase is due to the difference in the inter molecular forces.
Thus, assertion is wrong but statement R is correct.
Hence, option (d) is correct answer.