question_answer

The C?H bond distance is the longest in

A) \[{{C}_{2}}{{H}_{2}}\]                    

B) \[{{C}_{2}}{{H}_{4}}\]

C) \[{{C}_{2}}{{H}_{4}}B{{r}_{2}}\]                 

D) \[{{C}_{6}}{{H}_{6}}\]

Correct Answer: C

Solution :

As the 5-character or number of \[\pi -\]electrons increases, bond length decreases. Therefore, \[{{C}_{2}}{{H}_{4}}B{{r}_{2}}\]due to the absence of \[\pi -\]electrons or due to the presence of lesser s-character (25%), has the longest C?H bond distance.