Question

write balanced chemical equations for the following statements (1)Bleaching powder is kept open in air (2) blue crystals of copper sulphate are heated (3) chlorine gas is a passed through dry slaked lime (4)carbon dioxide gas is passed through lime water (5)NaOHsolution is heated with zinc granules.

Answer 1

CaOCl2(s) + CO2(g) = CaCO3(s) + Cl2(g)CuSO4.5H2O (when heated)= CuSO4 + 5H2O

CuSO4 after reaction is white in colour

Answer 2

Answer: (1) Bleaching powder is kept open in air: It absorbs carbon dioxide and produces calcium carbonate and liberate chlorine which is used for disinfection.

$CaOCl_2+CO_2\rightarrow CaCO_3+Cl_2$

2) blue crystals of copper sulphate are heated: Copper sulfate is blue in its hydrated form and colorless in anhydrous form.

$CuSO_4.5H_2O\rightarrow CuSO_4+5H_2O$

3) chlorine gas is a passed through dry slaked lime, it produces bleaching powder and water.

$CL_2+Ca(OH)_2\rightarrow CaOCl_2+H_2O$

4) carbon dioxide gas is passed through lime water- lime water turns milky due to formation of calcium carbonate.

$CO_2+Ca(OH)_2\rightarrow CaCO_3+H_2O$

5) NaOH solution is heated with zinc granules: result into formation of sodium zincate and evolve hydrogen gas.

$Zn+NaOH\rightarrow Na_2ZnO_2+H_2$