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18
MCQ (Multiple Correct Answer)

Which of the following is the correct representation for intermediate of nucleophilic addition reaction to the given carbonyl compound (A)?

A
B
C
D
19
Subjective

Why is there a large difference in the boiling points of butanal and butan-1-ol?

Explanation

Butan-1-ol has intermolecular H-bonding as shown below

Butanol has polar $\mathrm{O} — \mathrm{H}$ bond due to which it shows intermolecular H -bonding which is not possible in case of butanal due to absence of polar bond. Instead of it has only weak dipole-dipole interactions. Hence, butanal has higher boiling point than butan-1-ol.

20
Subjective

Write a test to differentiate between pentan-2-one and pentan-3-one.

Explanation

lodoform test (yellow ppt. formed when heated with sodium hypohalite) Pentan-2-one gives positive test as it contains $-\mathrm{COCH}_3$ group whereas pentan-3-one does not.

21
Subjective

Give the IUPAC names of the following compounds.

Explanation

Following are the IUPAC names of the compounds

22
Subjective

Give the structure of the following compounds.

(a) 4-nitropropiophenone

(b) 2-hydroxycyclopentanecarbaldehyde

(c) Phenyl acetaldehyde

Explanation