(i) The HCH bond angle in H2C=O
(ii) The CNH bond angle in (CH3)2NH
(iii) The COH bond angle in CH3OH
How do you do it? do you have to figure out if the hybridization C atom is an sp sp2 or sp3?
2 Answers

First you want to draw the Lewis Structures. Calculate the valence electrons and assign the bond and lone pairs according to the octet rule or exceptions as they apply. Once you’ve found those then based on the list below you can determine the bond angles. The hybridization has a trick that I use…. Count each letter as though it has 1 next to it, and they will correspond to the total amount of pairs with the respective geometries. (Ex: Linear is sp that is like s1p1 so the geometry is 2….. Tetrahedral is sp3…. the geometry for each in its list is 4 and so on)
The bond angles are as follows:
Linear 180 degrees 2 bond pairs, 0 lone pairs. (Hybridization: sp)
Trigonal Planar 120 degrees 3 bond pairs, 0 lone pairs (Hybridization: sp2)
Bent 2 bond pairs, 1 lone pair
Tetrahedral 109.5 degrees 4 bond pairs, 0 lone pairs (Hybridization: sp3)
Trigonal Pyramidal 3 bond pairs, 1 lone pair
Bent 2 bond pairs, 2 lone pairs
Trigonal Bipyramidal 90, 120, 180 degrees 5 bond pairs, 0 lone pairs (Hybridization: sp3d)
Seesaw 90, 120, 180 degrees 4 bond pairs, 1 lone pair
TShaped 90, 180 degrees 3 bond pairs, 2 lone pairs
Linear 180 degrees 2 bond pairs, 3 lone pairs
Octahedral 90, 180 degrees 6 bond pairs, 0 lone pairs ((Hybridization: sp3d2)
Square pyramidal 5 bond pairs, 1 lone pair
Square Planar 4 bond pairs, 2 lone pairs
It may not be entirely clear but ask questions as you may need.

Okay when we draw and count the hypdrization for each letter then how we have the total if we have an example each letter is sp3 then we take that the whole compaund is sp3