Explanation:
(c) \(\%\) of \(C = \frac{{{\rm{Mass}}\,\,{\rm{of}}\,\,C}}{{{\rm{Mass}}\,\,{\rm{of}}\,\,{\rm{substance}}}} \times 100\)
\(CC{l_4} = \frac{{12}}{{154}} \times 100 = 7.79\,\% \)
\({C_6}{H_6}C{l_6} = \frac{{72}}{{291}} \times 100 = 24.74\,\% \)
\(C{H_2}OH - C{H_2}OH = \frac{{24}}{{62}} \times 100 = 38.70\,\% \).