(2) in the collection of CO2 in a soft plastic bottle (as shown in Figure B), add the appropriate amount of NaOH solution, cover the stopper and shake, the bottle deflated, so that the CO2 reacted with the NaOH, Qu questioned the cause of the deflated soft plastic bottles may also be the cause of carbon dioxide soluble in water;
(3) in the soft plastic bottle (as shown in Figure B), the bottle deflated, so that the CO2 reacted with NaOH, Qu questioned the cause of the deflated soft plastic bottles may also be the cause of carbon dioxide dissolved in water;
(3) The reaction between CO2 and NaOH has the production of sodium carbonate, so if you add calcium chloride solution will have a white precipitate, it proves that the reaction between CO2 and NaOH has indeed occurred.
The answers are:
(1) bubbles coming out of the bottom of the test tube;
(2) carbon dioxide dissolves in water;
(3) calcium chloride.