Question 1 (10 marks) Silver arsenate (Ag3AsO4) is a slightly soluble salt with Ksp = 1.0x10-22 M4 at 25 °C. Ag3AsO4(s) ↔ 3Ag+(aq) + AsO43-(aq) i. Calculate the molar solubility of silver arsenate in pure water at 25 °C. ii. Calculate the molar solubility of silver arsenate in 0.10 M AgNO3. Question 2 (10 marks) Milk of magnesia is an ‘over the counter’ pharmaceutical preparation used as a laxative and for heartburn. It can be prepared by saturating water with magnesia (MgO). At 25 °C, a magnesia suspension has a pH of 10.16. Write a balanced equation for the equilibrium between the MgO(s) and the ions it produces in solution. Calculate the equilibrium constant for this reaction at 25 °C. What is the solubility of MgO in water? Question 3 (10 marks) Estimate the pH of 0.001 M solutions of the following: i. HNO3 ii. KOH iii. Na2CO3 iv. NaCl v. Phenol ...

1. Question 1 (10 marks)
Silver arsenate (Ag3AsO4) is a slightly soluble salt with Ksp =
1.0x10-22 M4 at 25 °C.
Ag3AsO4(s) ↔ 3Ag+(aq) + AsO43-(aq)
i. Calculate the molar solubility of silver arsenate in pure
water at 25 °C.
ii. Calculate the molar solubility of silver arsenate in 0.10 M
AgNO3.
Question 2 (10 marks)
Milk of magnesia is an ‘over the counter’ pharmaceutical
preparation used as a laxative and for heartburn. It can be
prepared by saturating water with magnesia (MgO). At 25 °C, a
magnesia suspension has a pH of 10.16. Write a balanced
equation for the equilibrium between the MgO(s) and the ions it
produces in solution. Calculate the equilibrium constant for this
reaction at 25 °C. What is the solubility of MgO in water?
Question 3 (10 marks)
Estimate the pH of 0.001 M solutions of the following:
i. HNO3
ii. KOH
iii. Na2CO3
iv. NaCl
v. Phenol