Question

Assertion: The carbon in ethyne is more eletronegative compared to ethene
Reason: More is the s-character more electronegative is the atom

• A. Both assertion and reason are correct but reason is not the correct explanation of the assertion
• B. Both assertion and reason are correct and reason is also the correct explanation of the assertion
• C. Assertion is correct but the reason is wrong
• D. Assertion is wrong but the reason is correct

Answer 1

The correct option is B Both assertion and reason are correct and reason is also the correct explanation of the assertion

The chemical formula of ethyne is $CH\equiv CH$
So here carbon is bonded to only two atoms. Hence it is $sp$ hybridised.

The chemical formula of ethene is $C{H}_2=C{H}_2$. Hence, carbon is bonded to three atoms, two hydrogen atoms and one carbon atom. Thus in ethene carbon is $s{p}^2$ hybridised.

Again, s character in $s{p}^2$ hybridised atom is $33.33\%$ while s character in $sp$ hybridised atom is $50\%$.

We also know that more is the s character more is the eletronegativity of the atom. Thus the reason is correct and it also explains the assertion correctly.
Hence option b is the correct answer.