chem question please help if you can it deals with LeChateliers principle and equlibrium equations?

Question

a) The carbon dioxide of the atmosphere, being a nonmetallic oxide and acid anhydride, has a low solubulity in rain water but produces a slightly acidic solution. Write an equilibrium equation for the dissolution of carbon dioxide in water and identify the acid that is formed.

b) Calcium carbonate, the major component of limestone, is slightly soluble in water. Write an equilbrium equation showing the slight solubility of calcium carbonate in water.

c) Write a Bronsted equation for the weak acid formed in part a, showing how it produces hydronium ion in aqueous solution.

d) Using LeChateliers principle, explain how the weak acid formed in rainwater causes the dissolution of calcium carbonate. the consequence of this reaction contributes to the degree of hardness in underground and surface water supplies and also accounts for the formation of stalagmites and stalactites.

Answer 1

a) CO2 + H2O >> H2CO3
carbonic acid

b) CaCO3 <----> Ca2+ + CO32-
Ksp = 2.8 x 10^-9 = [Ca2+] [ CO32-]

c) H2CO3 is a diprotic acid :
H2CO3 + H2O <---> HCO3- + H3O+

d) water in aquifers underground can be exposed to levels of CO2 much higher than atmospheric.
A such water percolates trough calcium carbonate rock , the CaCO3 dissolves.
When that same water emerges from the tap , in time it comes into equilibrium with CO2 levels in the air out gassing its excess CO2.
CaCO3 becomes less soluble as a result and the excess precipitates as a lime scale.
This same process is responsible for the formation of stalagmites and stalactites.
HCO3- + H2O <-----> CO32- + H3O+

Answer 2

a) H2O -> H+ + OH-
OH- + CO2 -> HCO3-
HCO3- + H+ -> H2CO3

Carbonic Acid

b) CaCO3 -> Ca2+ + CO3(2-)
Rest as above

c) H2CO3 + H2O -> H3O+ + HCO3-

d) CO3(2-) is leached away.