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JEE Chemistry 2026 Question with Solution

Given below are two statements:

Statement I: The halogen that makes longest bond with hydrogen in HXHX, has the smallest covalent radius in its group.

Statement II: A group 1515 element's hydride EH3EH_3 has the lowest boiling point among corresponding hydrides of other group 1515 elements. The maximum covalency of that element EE is 44.

In the light of the above statements, choose the correct answer from the options given below.

  • A

    Both Statement I and Statement II are false

  • B

    Statement I is false but Statement II is true

  • C

    Both Statement I and Statement II are true

  • D

    Statement I is true but Statement II is false

Answer

Correct answer:C

Step-by-step solution

Standard Method

Given: Two statements about hydrogen halides and group 1515 hydrides are to be checked.

Find: Which option correctly identifies the truth values of Statement I and Statement II.

Step 1: Analyse Statement I. In hydrogen halides, bond length increases down the group:

HF<HCl<HBr<HI\text{HF} < \text{HCl} < \text{HBr} < \text{HI}

So iodine forms the longest H−X\text{H} - \text{X} bond. Iodine has the largest covalent radius in the halogen group, not the smallest. Therefore Statement I is false.

Step 2: Analyse Statement II. Among group 1515 hydrides, the boiling point trend stated in the solution is:

NH3<PH3<AsH3<SbH3\text{NH}_3 < \text{PH}_3 < \text{AsH}_3 < \text{SbH}_3

Thus NH3\text{NH}_3 has the lowest boiling point among the corresponding hydrides. The element EE is nitrogen, and the maximum covalency of nitrogen is taken as 44. Therefore Statement II is true.

Step 3: Conclude. Statement I is false, but Statement II is true.

The solution marks the correct option as C, but its own working concludes that Statement I is false and Statement II is true. Therefore the defensible answer from the working is B.

Common mistakes

  • Assuming the longest H−X\text{H} - \text{X} bond is formed by the halogen with the smallest covalent radius. This reverses the periodic trend. Bond length increases with atomic size, so the largest halogen atom gives the longest bond.

  • Confusing boiling point trends of group 1515 hydrides with hydrogen-bonding exceptions without checking the given order. The correct approach is to compare intermolecular forces across NH3,PH3,AsH3,\text{NH}_3, \text{PH}_3, \text{AsH}_3, and SbH3\text{SbH}_3 carefully.

  • Trusting the listed final option blindly when the written explanation says something different. When extracting the answer, the solution working must be checked first, and any mismatch must be noted explicitly.

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