Anbspbuffer consists of 033 m h3po4nbspand 01 m nah2po4

Question

1. Calculate the pH during the titration of 25.00 mL of 0.1000 M HF(aq) with 0.1000 M RbOH(aq) after 15 mL of the base have been added. K_a of HF = 7.4 x 10^-4.

2. A buffer consists of 0.33 M H₃PO₄ and 0.1 M NaH₂PO₄. Given that the K values for H₃PO₄ are, K_a1 = 7.2 x 10^-3, K_a2 = 6.3 x 10^-8, and K_a3 = 4.2 x 10^-13, calculate the pH for this buffer.

3. Determine the volume in mL of 0.22 M NaOH(aq) needed to reach the half equivalence (stoichiometric) point in the titration of 36 mL of 0.18 M C₆H₅COOH(aq). The K_a of benzoic acid is 6.5 x 10^-5.