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NEET Chemistry Solved Question Paper 2003

Multiple Choice Questions

51.

Assertion : Trans-2-butene on reaction with Br₂ gives meso-2,3-dibromobutane.

Reason : The reaction involves syn -addition of bromine.

If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

If assertion is true but reason is false.

With trans-2-butene, the product of Br₂ addition is optically inactive due to the formation of symmetric mesa compounds.

52.

Assertion : Benzyl bromide when kept in acetone water it produces benzyl alcohol.

Reason : The reaction follows S_N2 mechanism.

If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

If both assertion and reason are true and the reason is the correct explanation of the assertion.

When benzyl bromide is kept in acetone, it produces benzyl alcohol.

53.

Subunits present in haemoglobin are

Haemoglobin is made up of four polypeptide subunits, two alpha (α) and two beta (β) subunits. Each of the four subunits consists of a heme molecule and each of them is capable of taking up one molecule of O₂. Therefore, oxyhaemoglobin can be represented as Hb(O₂)₄.

54.

Which one of the following is not a surfactant?

CH₃ - (CH₂)₁₅ - (CH₃)₂N⁺ - CH₃Br^-
CH₃ - (CH₂)₁₄ - CH₂ - NH₂
CH₃ - (CH₂)₁₆ - CH₂OSO₂^-Na⁺
OHC - (CH₂)₁₄ - CH₂ - COO^-Na⁺

CH₃ - (CH₂)₁₄ - CH₂ - NH₂

In order to act as a surfectant, molecule should have both polar and non-polar ends.

55.

Assertion : Glycosides are hydrolysed in acidic conditions.

Reason : Glycosides are acetals.

If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

If both assertion and reason are false.

Glycosides are formed by treating glucose with CH₃OH in the presence of dry HCl gas and can be hydrolysed by strong reagents like HCN, NH₂OH and C₆H₅NHNH₂. Also, glycosides are known as hemi-acetals.

56.

Assertion : Hydroxyketones are not directly used in Grignard reaction.

Reason : Grignard reagents react with hydroxyl group.

If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

If both assertion and reason are true and the reason is the correct explanation of the assertion.

Hydroxyketones are not directly used in Grignard reaction as these are very reactive and will react with hydroxyl group.

57.

Propan-1-ol can be prepared from propene by

H₂O/H₂SO₄
Hg(OAc)₂/H₂O followed by NaBH₄
B₂H₆ followed by H₂O₂
CH₃CO₂H/H₂SO₄

B₂H₆ followed by H₂O₂

Hydroboration yields 1° alcohol from alkenes.

3CH₃CH=CH₂ $\to_{THF}^{{BH}_{3} in}$ (CH₃CH₂CH₂)₃B $\overset{3 H_{2} O_{2}}{\to}$ $\underset{1 - propanol}{3 {CH}_{3} {CH}_{2} {CH}_{2} OH} + H_{3} {BO}_{3}$

58.

Time required to deposit one millimole of aluminium metal by the passage of 9.65 amperes through aqueous solution of aluminium ion is

30 s
10 s
30,000 s
10,000 s

10 s

Al³⁺ + 3e^- → Al

For deposition of 1 gm of equivalent = 96500 C

For deposition of 1 millimole = 96.500 C

As Q = It ⇒ t = $\frac{Q}{I} = \frac{96.5}{9.65} = 10 s$

59.
Which one of the following is not a buffer solution?

0.8M H₂S + 0.8M KHS

2M C₆H₅NH₂ + 2M C₆H₅NH₃^-Br^-

3M H₂CO₃ + 3M KHCO₃

0.05M KClO₄ + 0.05M HClO₄

0.05M KClO₄ + 0.05M HClO₄

Buffer solutions can be obtained by mixing a weak acid with its salt formed with a strong base or by mixing a weak base with its salt formed with a strong acid.

Among all the options given, option d is correct. As HClO₄ is a strong acid, therefore equimolar mixture of HClO₄ and its salt KClO₄ is not a buffer solution.

60.

Assertion : Activity of an enzyme is pH dependent.

Reason : Change in pH affects the solubility of the enzyme in water.

If both assertion and reason are true and the reason is the correct explanation of the assertion.
If both assertion and reason are true and the reason is not the correct explanation of the assertion.
If assertion is true but reason is false.
If both assertion and reason are false.

If both assertion and reason are true and the reason is not the correct explanation of the assertion.

Enzymes are proteins which act as catalyst for bio-chemical reactions. pH affect their activity as protonation-deprotonation may cause denaturation of the protein structure. Solubility is also affected.