CBSE Class 10 Science 2019 · Paper 31/5/1 · Question 23(b)

(i) Sodium hydrogen carbonate (baking soda), ${\text{NaHCO}}_3$; sodium carbonate, ${\text{Na}}_2{\text{CO}}_3$, also gives carbon dioxide. (ii) ${\text{CH}}_3\text{COOH}+{\text{NaHCO}}_3\to {\text{CH}}_3\text{COONa}+{\text{H}}_2\text{O}+{\text{CO}}_2$ (with sodium carbonate: $2{\text{CH}}_3\text{COOH}+{\text{Na}}_2{\text{CO}}_3\to 2{\text{CH}}_3\text{COONa}+{\text{H}}_2\text{O}+{\text{CO}}_2$) (iii) Pass the gas through lime water (calcium hydroxide solution) with a delivery tube dipping into it: the lime water turns milky, which shows the gas is carbon dioxide. ${\text{Ca(OH)}}_2+{\text{CO}}_2\to {\text{CaCO}}_3+{\text{H}}_2\text{O}$