Question

Acetic acid is obtained when:
A.Methyl alcohol is oxidised with potassium permanganate
B.Calcium acetate is distilled in the presence of calcium formate
C.Acetaldehyde is oxidised with potassium dichromate and sulphuric acid
D.Glycerol is heated with sulphuric acid.

Answer 1

Hint: Acetic acid is a colourless organic compound with molecular formula $C{H_3}COOH$. The IUPAC name of acetic acid is ethanoic acid. In undiluted form, sometimes it is also called glacial acid.

Complete step by step answer:
Acetic acid is obtained when acetaldehyde is oxidised with potassium dichromate and sulphuric acid and the corresponding reaction is given below:

$C{H_3}CHO\xrightarrow[{}]{{KMn{O_4} or {K_2}Cr_2^{}{O_7}}}C{H_3}COOH$
Aldehydes are easily oxidised by the strong and even mild oxidising agent because of the presence of hydrogen atom on the carbonyl group which can be converted in OH group without involving the cleavage of any other bond.
If we talk about other options then we will see that methyl alcohol is oxidised with potassium permanganate to give formic acid having molecular formula HCOOH. And when calcium acetate is distilled in the presence of calcium formate it gives acetaldehyde.
Hence the correct answer is option (C).

Note:
When aldehydes are oxidised it gives acid with the same number of carbon. Due to presence of hydrogen atom with carbonyl group it gets oxidised with the help of mild oxidising agent also. So it acts as a strong reducing agent. It can reduce tollen’s reagent, fehling’s solution and Benedict’s solution also. Acetic acid is one of the most important carboxylic acids and a good cleaner and disinfectant.