Question

In which of the following compounds, all the bond angles are exactly ${109}^{\circ }{28}^{\prime }$

• A. Chloromethane
• B. Iodoform
• C. Carbon tetrachloride
• D. Chloroform

Answer 1

The correct option is C Carbon tetrachloride

Generally molecules having $s{p}^3$ hybridisation and having no lone pairs of electrons possess bond angles around ${109}^{\circ }{28}^{\prime }$. But to have bond angle which is exactly equal to ${109}^{\circ }{28}^{\prime }$ the molecule shoud also be symmetrical, so as to get same bond pair - bond pair repulsion.
Here, chloromethane ($C{H}_{3}Cl$), iodoform ($CH{I}_3$), carbon tetrachloride ($CC{l}_4$) and chloroform $(CHC{l}_3$), all are $s{p}^3$ hybridised but since only $CC{l}_4$ is perfectly symmetrical thus only $CC{l}_4$ has bond angles which are exactly equal to ${109}^{\circ }{28}^{\prime }$.