Assertion : Acetylene on reacting with sodamide gives sodium acet…

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MCQ

Assertion : Acetylene on reacting with sodamide gives sodium acetylide and ammonia.

Reason : $sp$ hybridised carbon atoms of acetylene are considerably electronegative.

✓
If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.
B
If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.
C
If the Assertion is correct but Reason is incorrect.
D
If both the Assertion and Reason are incorrect.

✓

Answer

Correct option: A.

If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

a
Acetylene on reaction with sodamide gives sodium acetylide and ammonia.

$CH\equiv CH\xrightarrow{NaN{{H}_{2}}}\underset{\begin{smallmatrix}
monosodium \\
acetylide
\end{smallmatrix}}{\mathop{HC\equiv \bar{C}\,\overset{+}{\mathop{N}}\,a}}\,+N{{H}_{3}}$

Here formation of sodium acetylide can be explained bt $sp-$ hydridisation of carbon atoms. As we know that an electron in $s-$ orbital is more tightly held than in a $p-$ orbital. In $sp$ hydridisation, $s-$ character is $50\%$ as compared to $sp^2\,(33\%)$ or $sp^3\,(25\%)$. So, due to large $s-$ character the carbon atom is quite electronegative and hence $Na$ of $NaNH_2$ can replace $H^+$ of $C-H$ bond.

Hence assertion and reason both are true and reason is the correct explanation of assertion.