Ask the master three chemistry questions

1.The mass is the same, the mass fraction of H2SO4 and NaOH are the same, but the mass is different, you may wish to set the mass to 1, then H2SO41 98, NaOH is 1 80, so the NaOH is excessive, and the purple litmus solution is blue.

2NaOH+H2SO4=Na2SO4+H201 (overdose) 1

dilute hydrochloric acid, because 2HCl+Na2CO3=H20+2NaCl+CO2; (The NaOH solution has deteriorated

2NaOH + CO2 = Na2CO3 + H2O) carbon and oxygen: carbon is reducible, oxygen is oxidizing;

d.Carbon monoxide and carbon dioxide: carbon monoxide is mainly reducing, carbon dioxide is oxidizing;

b.Sodium hydroxide and calcium hydroxide: both are alkalis and have the general properties of alkalis; c.Dilute hydrochloric acid and dilute sulfuric acid: both are acids, which have the general properties of acids

XG Obviously, the amount of sodium hydroxide is insufficient, and the drops of litmus appear red.

All are non-metallic elements, B are all alkalis, and C are all acids

NaOH is more blue than H2SO4=98 than 80 bases.

na2co3+2hcl=2nacl+h2o+co2d

b is both acid and c is base.

1.Sodium hydroxide excess is blue (in moles)2Select b dilute hydrochloric acid and deteriorated sodium carbonate to produce carbon dioxide 3Selected from the perspective of redox analysis).

For the first case, it can be seen that the solute mass of sulfuric acid and sodium hydroxide is equal, assuming that it is 98g, the amount of sulfuric acid is 1mol, but the amount of sodium hydroxide is that according to H2SO4 + 2NaOH = Na2SO4 + 2H2O, it can be seen that sulfuric acid reacts with sodium hydroxide in the ratio of 1::2, in fact, the amount of sodium hydroxide is excessive, so the solution is alkaline after the reaction, and the color of the indicator is blue;

For the second question, the excess of sodium hydroxide makes sodium carbonate in the solution, so the reaction is actually a test of carbonate, in the three options, A and B both substances will appear, but for option A, calcium hydroxide is slightly soluble, and dropping calcium chloride into the alkaline solution will also produce white insoluble matter, there is interference, the best choice should be B, dropwise addition of hydrochloric acid will produce bubbles, 2HCl + Na2CO3 = 2NaCl + CO2 + H2O (gas symbol);

3. Select AD; For option a, carbon and oxygen, according to the position of the periodic table, oxygen has strong oxidizing property and carbon has strong reducing properties, and the properties are different; For option D, CO, CO2, carbon monoxide in the intermediate valence state of carbon in both oxidizing and reducing, carbon dioxide in the most ** only oxidizing, different properties;

In option B, both are alkalis and have similar properties, but they are different in solubility and alkaline strength, and option C is similar, both are acids and reflect acidity;