Calculate the pH for the following cases in the titration of 25.0mL of 0.2M cyanic acid (HCNO, pKa=3.66) with 0.2M RbOH solution:
a) before addition of RbOH(aq)
b)after addition of 12.50ml RbOH
c)after addition of 25.00ml RbOH
d)after addition of 30.00ml RbOH