NEET Chemistry 4

Question 1

Which of the following compounds shows geometrical isomerism?

Accepted Answer

2-butene

Answer

2-Butene (CH₃–CH=CH–CH₃) shows cis-trans geometrical isomerism because each double-bond carbon has two different substituents.

Question 2

In the Born-Haber cycle for NaCl formation, which step is endothermic?

Accepted Answer

Sublimation of Na

Answer

Sublimation of solid sodium to gaseous atoms is endothermic as energy must be supplied to overcome metallic bonding.

Question 3

The half-life of a first-order reaction is 693 seconds. The rate constant is approximately:

Accepted Answer

0.001 s⁻¹

Answer

For a first-order reaction, k = 0.693/t½ = 0.693/693 = 0.001 s⁻¹.

Question 4

Which of the following is NOT a transition element?

Accepted Answer

Zinc (Zn)

Answer

Zinc (Zn, [Ar]3d¹⁰4s²) is not a transition element because its d-orbitals are completely filled in both the element and its common ion (Zn²⁺).

Question 5

Which of the following is the correct order of boiling points of noble gases?

Accepted Answer

He < Ne < Ar < Kr < Xe

Answer

Boiling points of noble gases increase with atomic mass due to increasing London dispersion forces: He < Ne < Ar < Kr < Xe.

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