A chemical experiment was done in the senior high school entrance examination, and the following S questions were given: ① Purification of crude salt; ② preparation and collection of carbon dioxide; ③

A chemical experiment was done in the senior high school entrance examination, and the following S questions were given: ① Purification of crude salt; ② preparation and collection of carbon dioxide; ③ Preparation and collection of oxygen. (1) As shown in figure 1, the name of instrument A is iron shelf; According to the fact that there is hydrogen peroxide in the medicine pumped by A, A absorbs the preparation and collection of oxygen; In the laboratory, manganese dioxide and hydrogen peroxide are used to prepare oxygen, so 9 1 medicine is lacking, and it is manganese dioxide; The chemical equation of this experimental reaction is 2h2o2 &: Nbs left; Manganese dioxide and. Nbs left; . & nbs left; 2H2O+O2↑；

(2) Figure 2 shows the main steps of a student's experiment, and the correct order of these steps is small abd；; There is a mistake in A, and the way to correct it is to immerse the long-necked funnel below the liquid level;

(3) Hydrogen peroxide is liquid, manganese dioxide is solid, and the reaction does not need heating, so according to the fact that the generating device of carbon dioxide is a solid-liquid mixing device without heating, it is concluded that carbon dioxide can also be prepared from calcium carbonate and dilute hydrochloric acid, and the chemical equation is small A, small O3+2H, small l═ small A, small l2+ small O2 =+H2a; & nbs left;

(m) Sodium hydroxide reacts with magnesium chloride to generate magnesium hydroxide precipitate and sodium chloride, so the crude salt usually contains soluble impurities such as small Mg l2 in addition to insoluble impurities such as sediment, and the reagent that can be added is sodium hydroxide solution;

(5) In the filtration operation, a glass rod is used for drainage;

(6) As can be seen from the figure, when weighing, the positions of the articles and the weights are reversed, and the actual weight of the beaker = 3ag-2.6g = 26.mg;

So the answer is: (1) iron platform; ③; Manganese dioxide; 2H2O2 & ampNbs left; Manganese dioxide and. Nbs left; . & nbs left; 2H2O+O2↑；

(2) Little Abd; ; a； Immersing the long-necked funnel below the liquid level;

(3) Small A, small O3+2H, small L/ small A, small l2+ small O2 =+H2a;

Sodium hydroxide solution;

(5) drainage;

(6) The positions of articles and weights should be reversed for nine times; 26.m