Question

when 100mL of 0.1M NH4OH is added to 100mL of 0.1HCL,ph of solution is (pKb of NH4OH is 4.74)​

Answer 1

Answer:

NH4OH + HCl =====> NH4Cl. So when 0.1-M NH4OH is neutralized by HCl, NH4Cl will be obtained.

Its concentration will be =0.1/2= 0.05-M.

Since it is a salt of a weak base (NH4OH) and a strong acid ( HCl), the solution will be acidic.

Its pH will be

pH= ½{pKw - pKb- logC} here

pKw= 14

pKb- for NH4OH= 4.7447

(since Kb=1.8 x 10^-5)

log C= log(0.05)=- 1.3010

So pH= ½{14–4.7447+1.3010) = 10.5563/2

= 5.2782 . Ok.