Question

Solve the problems below and show the complete solution.
Determine the pH of a solution consisting of 0.15 M NH4Cl and 1.5 M NH3. The Kb of NH3 is 1.8x10-5.

Answer 1

$NH4Cl=0.15m$

$NH3=1.5m$

$Kb=1.8×10-5$

$pKb=-logKb$

$pKb=-log(1.8×10-5)$

$pKb=4.745$

$POH=pKb+log(salt/acid)$

$POH=4.745+log(0.15/1.5)$

$POH=3.745$

$PH+POH=14$

$PH=14-3.745$

$PH=10.26$