18. Aqueous Equilibrium

In order to create a buffer 7.510 g of sodium cyanide is mixed with 100.0 mL of 0.250 M hydrocyanic acid, HCN. What is the pH of the buffer solution after the addition of 12.0 mL of 0.300 M NaH? K_a = 4.9 × 10⁻¹⁰.

Consider the titration of 75.0 mL of 0.60 M HNO₂ with 0.100 M NaOH at the equivalence point. What would be the pH of the solution at the equivalence point? The K_a of HNO₂ is 4.6 × 10⁻⁴.

Calculate the pH of the solution resulting from the mixing of 55.0 mL of 0.100 M NaCN and 75.0 mL of 0.100 M HCN with 0.0090 moles of NaOH. 

How will you detect the endpoint of the titration of the borate ion with HCl?

Calculate the pH when 50.0 mL of 0.150 M KOH is mixed with 20.0 mL of 0.300 M HBrO (K_a = 2.5 × 10^-9)