Given below are two statements — Assertion (A) and Reason (R): Assertion (A): PH3 has lower boiling point than NH3. Reason (R): In liquid state, NH3 molecules are associated through hydrogen bonding,…

Question

Given below are two statements — Assertion (A) and Reason (R):

Assertion (A): $\mathrm{PH_3}$ has lower boiling point than $\mathrm{NH_3}$ .

Reason (R): In liquid state, $\mathrm{NH_3}$ molecules are associated through hydrogen bonding, but $\mathrm{PH_3}$ molecules are associated through Van der Waals forces.

Choose the most appropriate answer:

Paaras Thakur · Accepted Answer

Both (A) and (R) are correct but (R) is the correct explanation of (A). 🧠 NH3 has a higher boiling point than PH3 because NH3 molecules are associated through intermolecular hydrogen bonding — P is not electronegative enough to support H-bonding. 🗺️ Evaluate Assertion (A): - Boiling points: PH3 ≈ −87.7 °C; NH3 ≈ −33.4 °C - PH3 has a lower boiling point → A is TRUE ✓ Evaluate Reason (R): - In liquid NH3, molecules associate via N–H···N hydrogen bonds (N is electronegative, lone pair available as acceptor) - This intermolecular association requires extra energy to break → raises boiling point - R is TRUE ✓ Does R explain A? Yes — the intermolecular H-bonding in NH3 (absent in PH3) directly explains why NH3 has a higher boiling point. R is the correct explanation of A ✓ Answer: Both (A) and (R) are correct and (R) is the correct explanation of (A)

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Both (A) and (R) are correct and (R) is not the correct explanation of (A)

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(A) is not correct but (R) is correct

Answer

Both (A) and (R) are correct but (R) is the correct explanation of (A)

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(A) is correct but (R) is not correct

Given below are two statements — Assertion (A) and Reason (R): Assertion (A): PH3 has lower boiling point than NH3.…

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