The information on the label tells us that each molecule of solute in the solution contains two hydrogen atoms, which can be mixed with black powder CuO, MnO2, iron powder and carbon powder, and mixed with colorless liquid to produce gas. Common colorless liquids that meet the requirements are hydrogen peroxide (H2O2) and dilute sulfuric acid (H2SO4), in which black manganese dioxide mixed with hydrogen peroxide can release oxygen, which can be tested with wooden strips with Mars. Black iron powder can react with dilute sulfuric acid to generate hydrogen, which can be tested by burning wood strips. Because the reactant characteristics and reaction conditions for preparing oxygen and hydrogen are all solid-liquid normal temperature generating devices, among the three experimental devices A, B and C, C is the heating device of alcohol lamp, and A is the long-necked funnel, but it does not reach below the liquid level, so device B should be selected to facilitate dosing and control the reaction rate; Device d collects gas by exhausting air. If oxygen is collected, it enters through the short tube B, because the density of oxygen is greater than that of air. If hydrogen with a density lower than that of air is collected, it will enter from the long pipe A;

So the answer is: Suppose 1:

Put forward manganese dioxide (MnO 2) hypothesis; Hydrogen peroxide (H2O2);

Design experiments with wooden strips, and Mars extends into the test tube;

The experimental phenomenon is that the wooden strip with mars is rekindled;

Experimental conclusion ①2H2O2? MnO2？ . ? 2H2O+O2↑； ② Oxygen (O2);

Discussion b; b；

Hypothesis 2:

Put forward the hypothesis: iron powder (Fe) diluted sulfuric acid (dilute H2SO4);

Design an experiment to move the burning wooden stick close to the test tube mouth;

The experimental phenomenon is that the gas burns and the flame is light blue;

Experimental conclusions ① Fe+H2SO4 ═ FeSO4+H2 ↑;

② Hydrogen (or H2);

Discussion b; a.