List-I	List-II
A) ${\text{CH}}_4$	1) $104.5°$
B) ${\text{C}}_2{\text{H}}_4$	2) $109°{28}^1$
C) ${\text{C}}_2{\text{H}}_2$	3) $120°$
D) ${\text{H}}_2\text{O}$	4) $180°$

I)  In ${\text{CH}}_4$,   Carbon undergoes ${\text{sp}}^{\text{3}}$ hybridization.  So its bond angle is $109°{28}^1$.

II)  In ${\text{C}}_2{\text{H}}_4$, Carbon undergoes ${\text{sp}}^2$ hybridization. So its bond angle is $120°$

III)  In ${\text{C}}_2{\text{H}}_2$, Carbon undergoes $\text{sp}$ hybridization.  So its bond angle is $180°$

IV)  In ${\text{H}}_2\text{O}$, Oxygen undergoes ${\text{sp}}^{\text{3}}$ hybridization and it has two lone pairs of electrons. Because of lone pair – lone pair repulsions its bond angle decreases from $109°{28}^1$ to $104.5°$.  So its

bond angle is $104.5°$.