Observe the diagram given below and answer the questions :[Figure: a big test tube fitted with a two-holed cork and held on a stand; through one hole a thistle funnel reaches the liquid at the bottom, where sodium carbonate is placed; through the oth…

Answer: (a) Acetic acid and sodium carbonate; (b) carbon dioxide; (c) lime water turns milky; (d) sodium bicarbonate (NaHCO₃); (e) as vinegar for preserving food and flavouring.

(a) The reactants are acetic acid (CH₃COOH) and sodium carbonate (Na₂CO₃).

(b) Carbon dioxide is released, and it comes out as brisk effervescence in the big test tube.

(c) The gas is passed through freshly prepared lime water, which turns milky because of the white precipitate of calcium carbonate formed.

(d) Sodium bicarbonate (baking soda) can be used instead of sodium carbonate; it gives the same products: \(\mathrm{CH_3COOH + NaHCO_3 \rightarrow CH_3COONa + H_2O + CO_2\uparrow}\).

(e) Acetic acid is used as vinegar — a 4–8% solution — for preserving pickles, sauces and other food, and for flavouring. In industry it is used to make acetates, cellulose acetate, dyes and medicines.