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Because c is the concentration. So b, d are directly ignored.

A option hydrosulfuric acid is a weak acid that ionizes... But s2- is the second ionization, i.e., weak.

Option C sodium sulfide is a salt, so it is completely ionized, and S2- is hydrolyzed in water, but the degree of hydrolysis is not high, so the concentration of sulfur ions is much larger than that of item A.

So option C is the maximum.

The reason why b and d are excluded first is that the concentration of ions has nothing to do with volume, the answer to this question is c, because sodium sulfide is a strong electrolyte and will be completely ionized, so s2- is, hydrosulfuric acid in the answer a is a weak acid, it will not be completely ionized, it must be less than this number, so the answer is c.

The answer should be A, because there is no solution in sodium sulfide, and sodium sulfide will react with water to form sulfur element, hydrogen and sodium sulfate or sodium sulfite, so there is no S2- ion at all, so C and D are excluded, as for A and B, we can know that C(S2-) in A is, and B is, so A is selected

Hello. The answer is c

According to the question, determine the concentration, and the answer can directly exclude b d to see a ionization, and the hydrosulfide itself is a weak acid, and the first ionization is very incomplete, and the second ionization is even less, and the first ionization is the second level, and the 5th to the 7th power of 10 is a multiple, and you know how small the degree of secondary ionization is, and thus you know how small the concentration of sulfur ions in a is.

Look at c sulfur ions are weak acid ions, so they will be hydrolyzed, but note that hydrolysis is only a small part, not a lot.

1. Completely inject the dilute nitric acid in the separating funnel into the U-shaped tube, and then tilt the U-shaped tube until the liquid enters the separating funnel, close the separating funnel and switch the piston, and then fill it with dilute nitric acid.

2. Prevent the source of oxygen oxide nitric oxide in the air.

3. Add hot copper wire or solution (copper wire is good for heating).

4. It can be stopped automatically. The resulting nitric oxide presses the liquid to the right side of the U-tube, separating the lifted copper wire from the dilute nitric acid.

5. Open the rubber stopper, the colorless gas will turn reddish-brown after contact with air.

1. Completely inject the dilute nitric acid in the separating funnel into the U-shaped tube, and then tilt the U-shaped tube until the liquid enters the separating funnel, close the separating funnel switch piston, and the source can be filled with dilute nitric acid.

2. Prevent air from entering.

3. Heating copper wire.

4. It can be stopped automatically. The nitric oxide generated by the lifting will press the liquid to the right side of the U-tube, separating the copper wire from the dilute nitric acid.

5. Open the rubber stopper, the colorless gas will turn reddish-brown after contact with air.

, dilute ammonia is a weak base, in which NH3·H20 decomposes to produce OH- that makes the equilibrium move in reverse (!!) Here I assume that there is no free NH3, otherwise it is more troublesome).

B, the bisulfate is completely ionized, H+ increases, and KW is only related to temperature.

c, hydrolysis is the product of combined water ionization, which promotes water ionization and positive movement.

d, kw becomes larger, c(h+) becomes larger, and ph decreases.

2, A1, inhibits the ionization of water, hydrogen ions are mainly ionized by sulfurous acid, and hydroxide is ionized by water and is equal to the hydrogen ions ionized by water in solution.

2. Promote the ionization of water, and all hydrogen ions in the solution are ionized by water.

3. It should be neutral.

4. Inhibit the ionization of water, the same as 1.

x is ca, y is c, z is s, and a is caco3.

The chemical equation for the reaction of xy2 with water is.

cac2＋2h2o＝ca（oh）2＋c2h2↑。

Classmate, are you sure that your question is not wrong? It took me a long time to figure it out.

It is easy to think that it may be a reaction to acetylene, so guess that XY2 is calcium carbide, then the obtained solution should be clear lime water, X is calcium, Y is carbon, YO2 is CO2, A is calcium carbonate, and it can be seen that Z is sulfur, X is Ca element, Y is C element, Z is S element, A is CaCO3

Equation CAC2+2H2O=Ca(OH)2+C2H2