Calculate the pH of a buffer mixture of 0.05 M NH_(4)Cl and 0.12 M NH_(4)OH at 298 K. (Dissociation constant of ammonium hydroxide at 298 K is 1.8xx10^(-5)).

Calculate the pH of a buffer mixture of 0.05 M NH_(4)Cl and 0.12 M NH_

1.	Calculate the pH of a buffer mixture of 0.05 M NH_(4)Cl and 0.12 M NH_(4)OH at 298 K. (Dissociation constant of ammonium hydroxide at 298 K is 1.8xx10^(-5)).
Answer» Solution :`pK_(b)=-logK_(b)` = `-log1.8xx10^(-5)` = -(5.2553) = 4.7447 POH = `pK_(b)+"log"(["salt"])/(["BASE"])` = `4.7447+"log"(0.05)/(0.12)` = 4.74 - 0.38 = 4.36 `thereforepH=14-pOH` = 14 - 4.36 = 9.64