What is the pH of a solution of 40.0 ml of 0.800 M HCl titrated with 4.00 ml of 1.00 M Hydroxyl amine?

Answer 1

mols HCl = M x L = 0.800 x 0.040 = 0.032
mols HONH2 = M x L = 1.00 x 0.004 = 0.004
So you have 0.032-0.004 = 0.028 mols HCl remaining and the volume is 40 + 4 = 44 mL or 0.044 L.
So M HCl = mols/L and convert that to pH.