Question

The correct order of electronegativity of carbon in ethane, ethene and ethyne is

• A. ethane $<$ ethene $<$ ethyne
• B. ethyne $<$ ethene $<$ ethane
• C. ethene $<$ ethyne $<$ ethane
• D. ethene $<$ ethane $<$ ethyne

Answer 1

Answer: (A)

Hydrocarbons	Molecular formula	$\%$ s-character
Ethane	$C{H}_3-C{H}_3$	$25\%$
Ethene	$C{H}_2==C{H}_2$	$33\%$
Ethyne	$CH\equiv CH$	$50\%$

As we know that, electronegativity $\propto \%S$-character $\propto$ acidic character Hence, correct order of electronegativity in the given compounds is,
ethane $<$ ethene $<$ ethyne.