The question is incomplete, here is a complete question.
A solution is prepared at 25 °C that is initially 0.18 M in methylamine (CH₃NH₂), a weak base with
, and 0.35 M in methylammonium bromide (CH₃NH₃Br). Calculate the pH of the solution. Round your answer to 2 decimal places.
Answer : The pH of the solution is, 10.36
Explanation :
First we have to calculate the value of
.



Now we have to calculate the value of pOH.
Using Henderson Hesselbach equation :
![pOH=pK_b+\log \frac{[Salt]}{[Base]}](https://tex.z-dn.net/?f=pOH%3DpK_b%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BBase%5D%7D)
![pOH=pK_b+\log \frac{[CH_3NH_3Br]}{[CH_3NH_2]}](https://tex.z-dn.net/?f=pOH%3DpK_b%2B%5Clog%20%5Cfrac%7B%5BCH_3NH_3Br%5D%7D%7B%5BCH_3NH_2%5D%7D)
Now put all the given values in this equation, we get :


Now we have to calculate the pH.

Therefore, the pH of the solution is, 10.36