NEET Chemistry practice questions

Question 1

Identify a molecule which does not exist.

Accepted Answer

He₂

Answer

Li₂

Answer

C₂

Answer

O₂

Question 2

The rate constant for a first order reaction is 4.606 × 10⁻³ s⁻¹. The time required to reduce 2.0 g of the reactant to 0.2 g is:

Accepted Answer

500 s

Answer

100 s

Answer

200 s

Answer

1000 s

Question 3

The slope of Arrhenius plot (ln k vs 1/T) of first order reaction is −5 × 10³ K. The value of Eₐ of the reaction is. Choose the correct option for your answer. [Given R = 8.314 J K⁻¹ mol⁻¹]

Accepted Answer

41.5 kJ mol⁻¹

Answer

83.0 kJ mol⁻¹

Answer

166 kJ mol⁻¹

Answer

−83 kJ mol⁻¹

Question 4

Given below are half cell reactions:
MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O, E°(Mn²⁺/MnO₄⁻) = −1.510 V
½O₂ + 2H⁺ + 2e⁻ → H₂O, E°(O₂/H₂O) = +1.223 V
Will the permanganate ion, MnO₄⁻ liberate O₂ from water in the presence of an acid?

Accepted Answer

Yes, because E°cell = +0.287 V

Answer

No, because E°cell = −0.287 V

Answer

Yes, because E°cell = +2.733 V

Answer

No, because E°cell = −2.733 V

Question 5

Consider the following reaction and identify the product (P):
3-Methylbutan-2-ol, CH₃–CH(CH₃)–CH(OH)–CH₃ —(HBr)→ Product (P)

Accepted Answer

CH₃–C(Br)(CH₃)–CH₂–CH₃ (2-bromo-2-methylbutane)

Answer

CH₃CH=CH–CH₃

Answer

CH₃–CH(CH₃)–CH(Br)–CH₃ (2-bromo-3-methylbutane)

Answer

CH₃–C(CH₃)₂–CH₂Br

Question 6

A compound with a molecular formula of C₆H₁₄ has two tertiary carbons. Its IUPAC name is:

Accepted Answer

2,3-dimethylbutane

Answer

n-hexane

Answer

2-methylpentane

Answer

2,2-dimethylbutane

Question 7

Energy and radius of first Bohr orbit of He⁺ and Li²⁺ are: [Given R_H = 2.18 × 10⁻¹⁸ J, a₀ = 52.9 pm]

Accepted Answer

E(Li²⁺) = −19.62 × 10⁻¹⁸ J; r(Li²⁺) = 17.6 pm; E(He⁺) = −8.72 × 10⁻¹⁸ J; r(He⁺) = 26.4 pm

Answer

E(Li²⁺) = −8.72 × 10⁻¹⁸ J; r(Li²⁺) = 26.4 pm; E(He⁺) = −19.62 × 10⁻¹⁸ J; r(He⁺) = 17.6 pm

Answer

E(Li²⁺) = −19.62 × 10⁻¹⁶ J; r(Li²⁺) = 17.6 pm; E(He⁺) = −8.72 × 10⁻¹⁶ J; r(He⁺) = 26.4 pm

Answer

E(Li²⁺) = −8.72 × 10⁻¹⁶ J; r(Li²⁺) = 17.6 pm; E(He⁺) = −19.62 × 10⁻¹⁶ J; r(He⁺) = 17.6 pm

Question 8

Given below are two statements:
Statement-I: [Fe(ox)₃]³⁻ is chiral.
Statement-II: trans-[Cr(H₂O)₂(ox)₂]⁻ is chiral.
(Given: oxH₂ = HOOC–COOH)
In light of the above statements, choose the most appropriate answer from the options given below:

Accepted Answer

Statement-I is correct but Statement-II is incorrect.

Answer

Both Statement-I and Statement-II are correct.

Answer

Both Statement-I and Statement-II are incorrect.

Answer

Statement-I is incorrect but Statement-II is correct.