Give one method of preparing quick lime. What happens when rain water falls on it?
Calcium oxide is called quicklime. It is prepared by heating the lime stone in a rotatory kiln at 1070-1270 K.
CO2 formed escapes and hence the above equilibrium shifts towards the formation of calcium oxide.
When rain-water falls on quick lime, slaked lime is formed.
Name a few important uses of quick lime.
It is used:
(i) in the preparation of cement, glass and calcium carbide.
(ii) in the purification of sugar
(iii) in drying alcohol and non-acidic gases like ammonia etc.,
(iv) in softening of hard water.
(v) as a flux in the extraction of metals.
(vi) in agriculture as a fertiliser, disinfectant and germicide.
Starting with CaCO3, write balanced chemical equation showing the preparation of:
(i) CaO (ii) CaSO4 (iii) Ca(OH)2 (iv) Ca(HCO3)2 solution.
Describe two important uses of the following;
(a) Caustic soda (b) Sodium carbonate (iii) Quick lime.
(i) Caustic soda
It is used:
(a) in the manufacture of sodium metal, soap (from oils and fats), rayon, paper, dyes and drugs,
(b) for mercerising cotton to make cloth unshrinkable.
(ii) Sodium carbonate
It is used:
(a) in laundries and in softening of water as washing soda,
(b) in the manufacture of glass, caustic soda, soap powders etc.
(iii) Quick lime
It is used:
(a) in the purification of sugar and in the manufacture of dyestuffs,
(b) in the manufacture of bleaching powder, slaked lime and lime colours.
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