Question

What is the pH of 0.16 Moles of NH4Cl ( ammonium chloride, an ionic compound)?

Answer 1

Solution:

Lets write thw chemical equation for NH4Cl as NH4Cl when added to water it dissociates completely to NH4+ and Cl-

NH4Cl NH4⁺ + Cl^-

Use ICE table to calculate equilibrium concentration for this reaction

NH4+ NH3- + H+

Initial 0.16 0 0

Change -x x x

Equilibrium 0.16 - x x x

We know the Equilibrium constant for NH3 = 1.8 * 10^-5

Therefore,

Ka = x * x/(0.16 - x)

Kw/Ka = x2/0.16

We will eliminate x as the value is very small as compared

1 * 10-14/1.8 * 10-5 = x2 / 0.16

5.55 * 10-10 = x2/0.16

x = 9.428 * 10-6 = [H+]

pH = -log[H+]

= 5.02