Question

Which of the following has the smallest CH bond length among the following?

• A. $CH{F}_3$
• B. $CHC{l}_3$
• C. $CHB{r}_3$
• D. All have the same CH bond length

Answer 1

The correct option is A $CH{F}_3$

More electronegative elements tend to occupy the orbitals that has less s character. Flourine is the most electronegative element and it occupies the orbital that has less s-character. This increases the s character in the CH bond. Greater the s character, smaller the bond length and hence CH in $CH{F}_3$ has the smallest bond length among the four.