A mixture of $CH X_{3} Br$ and $CH X_{3} CH X_{2} Br$ is treated with sodium metal in dry ether (Wurtz reaction). Assume only C-C coupling takes place (no elimination). How many different alkanes are formed? (Enter an integer.)

Numerical answer type, tolerance 0.5.

Answer: 3

Coupling of two

CH X_{3}

groups gives ethane, two

CH X_{3} CH X_{2}

groups give butane and one of each gives propane. The mixture therefore contains

CH X_{3} - CH X_{3}

CH X_{3} CH X_{2} CH X_{3}

and

CH X_{3} CH X_{2} CH X_{2} CH X_{3}

. The count is 3.