(20 12? Xiaoming accidentally knocked over a bottle of vinegar while cleaning up the kitchen. Vinegar spilled on a pile of plant ash by the fire and found a lot.

[Inquiry activity 1] Clarifying the turbidity of lime water indicates that carbon dioxide is generated by the reaction, and in this reaction, carbon dioxide reacts with calcium hydroxide to generate insoluble calcium carbonate precipitate and water;

So the answer is: carbon dioxide (or CO2); ? ca(oh)2+co2═caco3↓+h2o；

[Investigation Activity 2]

The solution of (1) sodium carbonate is alkaline, but the solution of potassium carbonate is similar to that of sodium carbonate, so the solution of potassium carbonate is also alkaline, which can make phenolphthalein test solution turn red.

So the answer is: red;

(2) According to the meaning of the question, the main component of plant ash is potassium carbonate. When it reacts with dilute hydrochloric acid, the two compounds exchange components to generate potassium chloride and carbonic acid, and the latter is unstable and decomposes to generate carbonic acid;

Therefore, the answer is: K2CO3+2HCl = 2KCl+H2O+CO2 ↑; ?

(3)① According to the law of conservation of mass, the mass of carbon dioxide is 69g+100g-164.6g = 4.4g;

So the answer is: 4.4? g； ?

② Solution: Let the mass of K2CO3 in the sample be X and the mass of HCl consumed be Y..

K2CO3+2HCl=2KCl+H2O+CO2↑

138 7344

x？ y4.4？ g

138x=444.4g？ 138x=444.4g

Solution: x= 13.8? g？ y=7.3？ g

∴ The mass fraction of K2CO3 in the sample =13.8g 69g×100% = 20%.

③ Let the mass of hydrochloric acid with the required solute mass fraction of 14.6% be z 。

So z × 14.6% = 7.3g?

Solution: Z=50g.

A: The mass of carbon dioxide produced during the reaction is 4.4g；; ? The mass fraction of potassium carbonate in plant ash sample is 20%; ? To prepare 100g dilute hydrochloric acid for experiment, 50 g hydrochloric acid with solute mass fraction of 14.6% is needed.