Question

a soln. that is .195 M in CH3NH2 and .105 M in CH3NH3Br

what is the balanced equation for this ? How do you know ?

Answer 1

I'm thinking its
CH3NH3Br + H2O <====>H3O + CH3NH2

is this correct ?

Answer 2

Your equation looks ok to me but this looks like a buffer solution to me. Do you have a buffer problem? If so, use the Henderson-Hasselbalch equation to solve for the pH or the pKaa.