confusion of lime water test

[rosh2o_q2o]

Can anyone tell me how to perform lime water test in p3 chemistry for co2 to get carbonate ion....

 

[PlanetMaster]

Add equal parts of lime water and distilled water to the tall container. Add water and about an ounce of dry ice to the gas generator. Bubble CO2 through the lime water solution until the precipitate is well established (20-30 seconds), and then remove the tube and discuss the precipitate. Continue to bubble CO2 through the solution until the precipitate just disappears. Fill the test tube about 1/5 of the way full with the solution (or if a hot plate is being used, fill the beaker about 1/3 full and start it stirring on the hot plate). Begin bubbling air through the remainder of the solution, using the hose and glass tube from the generator. Discuss the significance of the re-dissolution and how the reaction can be reversed. Boil the solution for a couple of minutes with the Bunsen burner. The precipitate with reappear almost at once, but it takes about 10-20 minutes for the solution through which air is being bubbled to turn cloudy.

 

[rosh2o_q2o]

thank you very much...for your help but cant understand it well...can you plz tell me how to do it while conducting this experiment at the condition when we are given only A dilute acid, solution to be tested in a testtube, and lime water...along with all the observation throughout the experiment...

 

[Xenon]

Check the diagram:
http://www.btinternet.com/~chemistry.di ... ll-co2.htm

u will need to pass the CO2 liberated through the delivery tube to the other test tube containing limewater/ Ca(OH)2. this will give a white ppt of CaCO3/turn limewater milky.
Ca(OH)2 (aq) + CO2 (g) → CaCO3 (s) + H2O (l)

This ppt. will dissolve if excess CO2 is passed through limewater and the a clear solution is formed. CO2 will cause the CaCO3 ppt. to redissolve to form soluble Ca(HCO3)2/ calcium bicarbonate/calcium hydrogencarbonate.
CaCO3(s) + CO2(g) + H2O(l) → Ca(HCO3)2(aq)

 

[rosh2o_q2o]

thank you...very much i was confused abt the way of sending co2 into the limewater test tube...but you made it cleared thank you

 

[MAVtKnmJ]

As this is a lengthy process, you usually won't be asked to perform these kind of tests in an actual exam. Instead they just want you to write down the test :/