wat happens in the reaction of Cacl and Nahco3 wen water is added . i believe co2 is evolved.

wow, no clue couldnt even google it. Um, wats it look like, is it a precipation reaction?

I think the double replacement reaction that occurs would cause the bicarbonate anion to break down to carbon dioxide and carbonate anion. I've observed this when getting copper carbonate from reacting copper sulfate with sodium bicarbonate.

 

I'm not sure why this happens though.?

If you mean CaCl2, then it is possible that some CO2 is evolved:

 

CaCl2 + NaHCO3 --> CaCO3 + NaCl + H+ + Cl- (because CaCO3 is much more stable than Na or Ca bicarbonate)

 

Then, because some protons are produced, they react with the carbonate to give CO2:

 

2H+ + CO3(2-) --> H2O + CO2

 

 

This is just an educated guess, I don't know the exact reaction mechanism.

If you mean CaCl2' date=' then it is possible that some CO2 is evolved:

 

CaCl2 + NaHCO3 --> CaCO3 + NaCl + H+ + Cl- (because CaCO3 is much more stable than Na or Ca bicarbonate)

 

Then, because some protons are produced, they react with the carbonate to give CO2:

 

2H+ + CO3(2-) --> H2O + CO2

 

 

This is just an educated guess, I don't know the exact reaction mechanism.[/quote']

This guess is quite well. The bicarbonate is in equilibrium in its solutions:

 

2HCO3(-) <----> CO3(2-) + H2O + CO2

 

When either CO3(2-) or CO2 is removed from the right, then the bicarbonate decomposes irreversibly.

 

If you heat the solution, then the solubility of the CO2 is decreased and it bubbles out of the solution. This causes almost all bicarbonate to be decomposed.

 

If you add a solution of CaCl2, then the solubility product of Ca(2+) and CO3(2-) will be exceeded easily, especially if the concentration of CaCl2 is quite high. The result is precipitation of CaCO3, having the effect of taking CO3(2-) from the equilibrium. CaCO3 precipitates and CO2 bubbles out of solution. If you add a very small amount of CaCl2, then nothing will happen, because Ca(HCO3)2 is soluble quite well.

When Nahco3 is dissolved, CO2 forms. And then if you dissolve in CaCl, a double displacement happens, forming CaHCO3, and NaCl.