What molar concentration of ammonia will provide a hydroxyl ion concentration of 1.5×10-3 ?  Kb = 1.8 × 10-5

The reaction is NH3  +  H2O  ⇌  NH4+ +  OH-Kb = 1.8 × 10-5 = NH4+ OH-NH3 = 1.5×10-3 1.5×10-3NH3 = 1.8 × 10-5Equilibrium conc. of ammonia NH3   = 0.125 MAnd, total NH3   = 1.5 × 10-3 + 0.125 =0.13 M