# What is the approximate H—C—H bond angle in CH3^+?

The $H - C - H$ bond angle is ${120}^{\circ}$.
The carbon atom in the ion $\textcolor{b l u e}{C {H}_{3}^{+}}$ is $\textcolor{red}{s {p}^{2}}$ hybridized carbon and therefore, the geometry around this atom is trigonal planar. In this case, the $H - C - H$ bond angle is $\textcolor{b l u e}{{120}^{\circ}}$.
However, the carbon atom in $\textcolor{g r e e n}{C {H}_{4}}$ is $\textcolor{p u r p \le}{s {p}^{3}}$ hybridized carbon and therefore, the geometry around this atom is tetrahedral. In this case, the $H - C - H$ bond angle is $\textcolor{g r e e n}{{109.5}^{\circ}}$.