Question

1a.) From water sample, 10 mg/L HCO₃^- as CaCO₃, 10 mg/L CO₃^- as CaCO₃ and 50 mg/L Ca⁺ as CaCO₃ were measured. pH was near neutral. What is alkalinity?

_____ mg/L as CaCO3

1b.) From water sample, 10 mg/L HCO3- as CaCO3, 10 mg/L CO3- as CaCO3 and 50 mg/L Ca+ as CaCO3 were measured. pH was near neutral. What is alkalinity? _____ mg/L as CaCO3

1c.) Calculate K_sp = _____

A₂BO₃ ->2A⁺+ BO₃^2-
Molar concentration of A⁺ = Molar concentration of BO₃^2- = 2 M

1d.) pK_a2 equation for the following chemical reaction.
H₂SO₄ <-> H⁺ + HSO₄^- ; HSO₄^- <-> H⁺ + SO₄^-

Choices given:

		pKa2 = -log{[H+] [HSO4-]/[H2SO4]}
		pKa2 = -log{[H+] [H2SO4]/[HSO4-]}
		pKa2 = -log{[H+] [SO4-]/[HSO4-]}
		pKa2 = -log{[H+] [HSO4-]/[H2SO4]}

1e.) A water sample contains no chemicals before opening to the ambient air. Equilibrium is assumed between water and atmospheric CO₂. The Henry’s constant for carbon dioxide is 10 ^-3 M/atm at 25℃. The partial pressure of CO₂ is 10 ^-2 atm. pH of water is 6.8. Concentration of carbonate, CO₃^2- = _____ x 10^__ mg/L as CaCO₃

Answer 1

Alkalinity is the ability of water to neutralise acid. It can also be called as the buffering capacity of water.
Here is a detailed solution to all the parts of the question being asked.