1. At 25 C, a 0.500 M solution of ammonia (NH,) is 2.50% dissociated. Calculate the pH. [Answer: PH= 12.097] 2.Calculate the percent dissociation of a 0.20 mol/L solution of the weak acid HNO, if the pH of the solution is 5.10. [4.0 x 103 % (note that K. here is extremely small: 6.1 x 10-12)]