chemical equilibrium class 11

Question

what is the ph of solution which have 1 ml NH4OH (CONC 0.1M) 1ML  and (NH4)2SO4 concentration 0.05M given that kb(NH4OH)=10^-5

Answer 1

This assumes the ammonium ions formed from

NH4OH⇌NH⁺⁴+OH⁻

are negligible compared to those from the ammonium salt.

So [OH−]=2.10⁻⁵mol.dm⁻³

So pOH=4.7

So pH=14−4.7=9.3