Question

In the presence of manganese acetate, ethyne produces:

• A. acetic acid
• B. propanoic acid
• C. butanoic acid
• D. methanoic acid

Answer 1

Answer: (A)

acetic acid

Manganese acetate is an organometallic compound. Its action is like that of the Grignard reagent which first of all takes active hydrogen. Active hydrogen is the hydrogen attached to highly electronegative element like oxygen, nitrogen, chlorine. The electronegativity of $sp$ hybridised carbon lies between that of oxygen and nitrogen and so, hydrogen attached to it is the active hydrogen.

The reaction is as follows:
$Mn(C{H}_{3}COO{)}_2$ $+$ $HC\equiv CH$ $\to$ $2C{H}_{3}COOH$ $+$ $Mn\left(C_2\right)$