Question

In radical chlorination of alkanes, non-equivalent hydrogens react with chlorine atoms at different rates. At 35 °C, primary, secondary, and tertiary C-H bonds react at relative rates of 1 : 3.9 : 5.2 respectively. These are conditions of kinetic control where product ratios are determined by relative rates of formation. For example, if A is formed twice as fast as B, the A:B product ratio will be 2. Consider chlorination of the alkane below at 35 °C. 1. Specify the most reactive C-H bond(s), a-c. b Two non-equivalent C-H bonds of comparable reactivity should be separated by commas, i.e. a,c. 2. Specify the site of chlorination in the major monochloro substitution product, a-c. b Two products that form in comparable quantities should be separated by commas, i.e. a,c Submit Answer Retry Entire Group No more group attempts remain

Answer 1

1. Site: B since it is 2° hydrogen and has more reactivity rate 3.9.

2. Site a since it has total 18, 1° hydrogens.

Overall rate: 15.6(3.9x4 secondary hydrogens)

: 18 (1x18 primary hydrogens)

Total . :33.6

% of site : 15.6x100/33.6= 46.4%

% of site A: 18x100/33.6= 63.6 %

There are no hydrogen atoms at site C. Hence no reaction.