Question

What is the oxidation number of the underlined elements in the following and how do you rationalise your results?

CH₃COOH

Answer 1

CH₃COOH

2 (x) + 4 (+1) + 2 (−2) = 0

2x + 4 − 4 = 0

2x = 0

x = 0

However, 0 is average O.N. of C. The two carbon atoms present in this molecule are present in different environments. Hence, they cannot have the same oxidation number.

Thus, C exhibits the oxidation states of +2 and –2 in CH₃COOH.

\[\begin{array}{cc}
\ce{H}\phantom{.....}\ce{O}\phantom{.......}\\
|\phantom{......}||\phantom{.......}\\
\ce{H - C^{+2} - C^{-2} - O - H}\\
|\phantom{..............}\\
\ce{H}\phantom{..............}
\end{array}\]