Answer:
H2O> NH3> CH4
Explanation:
According to valence shell electron pair repulsion theory (VSEPR), bond angles and repulsion of electron pairs depends on the nature of electron pairs on the central atom of the molecule. Lone pairs cause more repulsion (and distortion of bond angles) than bond pairs). Lone pair- lone pair repulsion is greater than lone pair bond pair repulsion.
Water contains two lone pairs on oxygen hence it experiences the greatest repulsion. Ammonia has only one lone pair on nitrogen hence there is lesser repulsion between lone pairs and bond pairs. Methane possess only bond pairs of electrons hence it has the least repulsion.
I like ELA and Math because it motivates me to draw and sketch, which can help with me and my future plan.
pH is a symbolic representation of:

and for water we now that:

that means the text give us the information to calculate the concentration of protons and therefore the concentration of ions OH-:

therefore the concentration of OH- can be calculated:

but they are not asking about the concetration of OH- they ask about concentration of Ba(OH)2 and for that we need to know the disolution stechiometry

Whic mean the concentration of Ba(OH)2 is half the concentration of OH-:
Answer:
(−ΔH°1)+12(−ΔH°2)+(ΔH°3)+(ΔH°4)
I hope this helps you out!! :)