What is the pH of a solution prepared by mixing 50.00 cm3 of 0.10 M NH3 with 10.00 cm3 of 0.10 M NH4Cl?

Question

What is the pH of a solution prepared by mixing 50.00 cm3 of 0.10 M NH3 with 10.00 cm3 of 0.10 M NH4Cl? Assume that the volume of the solutions are additive and that Kb = 1.8 × 10-5 for NH3.

1. a. 11.13

2. b. 10.26

3. c. 9.95

4. d. 8.56

Answer 1

Moles NH3 = 0.0500 L x 0.10 = 0.00500

Moles NH4+ = 0.0100 L x 0.10 = 0.00100

total volume = 0.0600 L

Concentration NH3 = 0.00500 / 0.0600 = 0.0833 M

concentration NH4+ = 0.00100 / 0.0600 =0.0167 M

NH3 + H2O <------> NH4+ + OH-

1.8 x 10^-5 = ( 0.0167+x) (x) / 0.0833-x

x = [OH-] = 0.0000898 M

pOH = 4.047

pH = 14 - pOH = 9.95

Answer 2

no one wants to do your homework