Describe an activity with diagram to illustrate that the reaction of metal carbonates and metal bicarbonates with acids produces carbon dioxide. Write the relevant equations of all the reactions that take place. Name any two forms in which calcium carbonate is found in nature.
Aim: To show acid reacts with metal carbonate to liberate carbon dioxide.
Material Required: CaCO3(marble chips), Woulff-bottle, thistle funnel, dil. HCl, gas jar, matchbox, delivery tube bent at two right angles, lime water.
Procedure:
1. Take marble chips in a Woulff-bottle.
2. Set the apparatus as shown in diagram.
Reaction of calcium carbonate with dilute hydrochloric acid to liberate carbon dioxide gas which turns lime water milky and extinguishes burning matchstick
3. Add dil. HCl with the help of thistle funnel.
4. Collect the gas in gas jar by upward displacement of air.
5. Bring a burning matchstick near the gas jar and record your observations.
6. Pass the gas evolved through lime water and note down your observations.
Observations: The burning matchstick will get extinguished because carbon dioxide is neither combustible nor supporter of combustion. Lime water will turn milky due to formation of insoluble calcium carbonate. It can be used as test for CO2.
The chemical reactions taking place are as follows:
CaCO3(s) + 2HCl(dil.) →CaCl2(aq) + H2O(l) + CO2(g)
Ca(OH)2(aq) + CO2(g) →CaCO3(s) + H2O(l)
Conclusion: Metal carbonates react with dilute acids to liberate carbon dioxide. Limestone, chalk, marble are different forms of calcium carbonate. All metal carbonates and hydrogen carbonates react with acids to form corresponding salts, water and carbon dioxide.