Soda ash and baking soda are two common items in the kitchen, and they are both white solids. The fo

Question C analysis: sodium carbonate does not decompose when heated, sodium bicarbonate decomposes when heated to produce sodium carbonate, carbon dioxide and water, and there are still solid residues in the end, A is wrong; The flame color reaction of both substances is yellow, and B is wrong; Equal mass of sodium carbonate and sodium bicarbonate, the amount of sodium bicarbonate substance is large, and the amount of hydrochloric acid to generate carbon dioxide gas sodium bicarbonate is more, C is correct; Sodium carbonate solution, sodium bicarbonate solution and lime water all form calcium carbonate precipitate, D is wrong.

Comments: To distinguish sodium carbonate solution and sodium bicarbonate solution, hydrochloric acid can be added dropwise, the rate of gas production (sodium bicarbonate is fast) or the pH of two solutions of equal concentration can be determined (sodium carbonate solution is highly alkaline).

The main component of baking soda is NaHCO3, and the main component of soda ash is Na2CO3, A Baking soda is unstable, and it is easy to decompose into Na2CO3, CO2 and water when heated, and the mass is reduced, so A is correct;

B soda ash and baking soda both contain Na element, and the flame color reaction is yellow, which cannot be identified, so B is wrong;

C When reacting with hydrochloric acid, sodium bicarbonate produces carbon dioxide quickly, which can directly generate carbon dioxide gas, while sodium carbonate first forms sodium bicarbonate with hydrochloric acid, and then continues to react with hydrochloric acid to form carbon dioxide gas, which produces gas slowly, so C is wrong;

D Soda ash and baking soda both react with lime water to form calcium carbonate precipitate, so D is wrong so choose A