Predict the proportions of isomeric products from chlorination at room temperature of: (a) propane; (b) isobutane; (c) 2,3 - dimethylbutane; (d) n-pentane (Note: There are three isomeric products); (e) isopentane.

We will identify the structurally different hydrogens in each hydrocarbon. Here's the structural representation of each hydrocarbon: (a) propane: CH3-CH2-CH3 (b) isobutane: CH3-CH(CH3)-CH3 (c) 2,3-dimethylbutane: CH3-CH(CH3)-CH(CH3)-CH3 (d) n-pentane: CH3-CH2-CH2-CH2-CH3 (e) isopentane: CH3-CH(CH3)-CH2-CH3

The relative reactivity of hydrogen atoms depends on the degree of substitution. Primary H atoms (1°) are approximately 3.8 times less reactive than secondary H atoms (2°), and tertiary H atoms (3°) are approximately 5.0 times more reactive than 1° hydrogen. (a) Propane Primary H: 6 (2 x CH3) Secondary H: 2 (1 x CH2) Proportion: 100% primary (b) Isobutane Primary H: 6 (2 x CH3) Tertiary H: 1 (1 x CH) Proportion: 99.2% primary, 0.8% tertiary (c) 2,3-dimethylbutane Primary H: 4 (2 x CH3) Secondary H: 4 (2 x CH) Proportion: 50% primary, 50% secondary (d) n-pentane Primary H: 6 (2 x CH3) Secondary H: 6 (3 x CH2) Proportion: 61.5% primary, 38.5% secondary (e) isopentane Primary H: 6 (2 x CH3) Secondary H: 4 (2 x CH2) Tertiary H: 1 (1 x CH) Proportion: 79.1% primary, 20.3% secondary, 0.6% tertiary