Question

(i) Draw the structures of all isomeric alcohols of molecular formula C₅H₁₂O and give their IUPAC names.

(ii) Classify the isomers of alcohols in question 11.3 (i) as primary, secondary and tertiary alcohols.

Answer 1

(i) The structures of all isomeric alcohols of molecular formula, C₅H₁₂O are shown below:

(a)

Pentan-1-ol (1°)

(b)

2-Methylbutan-1-ol (1°)

(c)

3-Methylbutan-1-ol (1°)

(d)

2, 2-Dimethylpropan-1-ol (1°)

(e)

Pentan-2-ol (2°)

(f)

3-Methylbutan-2-ol (2°)

(g)

Pentan-3-ol (2°)

(h)

2-Methylbutan-2-ol (3°)

(ii) Primary alcohol: Pentan-1-ol; 2-Methylbutan-1-ol;

3-Methylbutan-1-ol; 2, 2−Dimethylpropan-1-ol

Secondary alcohol: Pentan-2-ol; 3-Methylbutan-2-ol;

Pentan-3-ol

Tertiary alcohol: 2-methylbutan-2-ol