Question

The C – H bond distance is longest in

• A. $C_2{H}_{2}B{r}_2$
• B. $C_2{H}_6$
• C. $C_2{H}_4$
• D. $C_2{H}_2$

Answer 1

The correct option is B

$C_2{H}_6$

Order of Bond length,

$\underset{C_2{H}_6}{\sigma \text{bond}\left(s{p}^3\right)}>\underset{C_2{H}_4\text{or}{C}_2{H}_{2}B{r}_2}{\sigma \text{bond}\left(s{p}^2\right)}>\underset{C_2{H}_2}{\sigma \text{bond}\left(sp\right)}$

More the character, the more electronegative the carbon. Hence, the carbon with higher electronegativity can pull electrons closer to its nucleus!