What is the original molarity of a solution of ammonia whose pH is 10.83

Answer 1

First, pH + pOH = pKw = 14. You know pH and pKw, solve for pOH, then
pOH = -log(OH^-). Then,
Kb = (NH4^+)(OH^-)/(NH3) and solve for (NH3)
Post your work if you get stuck.