Write balanced chemical equations for the following statements :
(i) NaOH solution is heated with zinc granules
(ii) Excess of carbon dioxide gas is passed through lime water
(iii) Dilute sulphuric acid reacts with sodium carbonate
(iv) Egg shells are dropped in hydrochloric acid
(v) Copper (II) oxide reacts with dilute hydrochloric acid.

Explanation

(i) `underset("Sodium hydroxide")(2NaOH(aq))+underset("Zinc")(Zn(s))overset(Delta)(rarr) underset("Sodium zinccate")(Na_(2)ZnO_(2)(aq))+underset("Hydrogen")(H_(2)(g))`
(ii) `underset("(lime water)")(Ca(OH)_(2)(aq))+CO_(2)rarr underset("(white ppt)")underset("calcium carbonate")(CaCO_(3)(s))+H_(2)O`
`CaCO_(3)(s)+CO_(2)(g) +H_(2)O(l) rarr underset("(Soluble in water)")underset("Calcium hydrogen carbonate")(Ca(HCO_(3))_2(aq))`
(iii) `H_(2)SO_(4)("dil")+Na_(2)CO_(3)(s) rarr underset("(Sodium sulphate)")(Na_(2)SO_(4))+CO_(2)+H_(2)O`
(iv) `underset("egg shell contains calcium carbonate")(CaCO_(3)(s))+2HCl rarr CaCl_(2)+H_(2)O+CO_(2)`
(v) `CuO(s) +2HCl(aq) rarr underset("(blue green)")underset("Copper chloride")(CuCl_(2)(aq))+H_(2)O(l)`