At 25 ºC the mixture will have a pH of

Question

100.0 mL of a 0.50 M aqueous NH₃ solution is mixed with 200.0 mL of 0.25 M aqueous HI. At 25 ºC the mixture will have a pH of

The correct answer is <7

Answer 1

If the choices for pH are 7, greater than 7 or less than 7, then the answer would be less than 7 since this is a titration of a weak base (NH3) with a strong acid HI. And since the moles of NH3 = moles HI, you are at the equivalence point, so the pH will be acidic.