Hydrocarbons 2 Question 32
32. Acidic hydrogen is present in
$(1985,1 \mathrm{M})$
(a) ethyne
(b) ethene
(c) benzene
(d) ethane
$(1984,1 \mathrm{M})$
(a) alkaline permanganate solution
(b) acidified permanganate solution
(c) neutral permanganate solution
(d) aqueous bromine solution
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Answer:
Correct Answer: 32. (c)
Solution:
- Terminal alkynes are slightly acidic, forms salt with very strong base like $\mathrm{Na}, \mathrm{NaNH}_{2}$ etc.
$$ \underset{\text { ethyne }}{\mathrm{H}}-\mathrm{C} \equiv \mathrm{C}-\mathrm{H}+\mathrm{Na} \xrightarrow{\Delta} \mathrm{H}-\mathrm{C} \equiv \mathrm{C}^{-} \mathrm{Na}^{+}+\frac{1}{2} \mathrm{H}_{2} \uparrow $$
