Question

Assume you are working with an acidic solution and you add soid CaCO3 to it. The following equilibrium reaction takes place.

2H+(aq)+CaCO3(s)<->Ca2+(aq)+CO2(g)+H2O(l)

a. What should you see visually upon the addition of the solid CaCO3?

b. After the addition of CaCO3 in part a, a student decided to bubble CO2 through the solution. What type of visual change would be expected?

Answer 1

a) given CaC03 is added to the solution

the reaction is

2H+ (aq) + CaC03 (s) ---> Ca+2 (aq) + C02 (g) + H20 (l)

CaC03 is white in color

so

upon the reaction , the white color disappears to form Ca+2 , C02 and H20

b)

now

given C02 is bubbled through the solution

according to Le Chatlier principle

the equilibrium will shift in a direction to counter the change

now

consider the reaction

2H+(aq) + CaCO3(s) <-> Ca2+(aq) + CO2(g) + H2O(l)

we are adding C02

so

to counter the change , the equilibrium try to reduce C02

so

it will shift towards the reactant side

so

we get more of CaC03 ( white precipitate )

so

upon bubbling C02 , the solution will become white because of the formation of CaC03 precipitate