Explore whether chemical reaction can occur between potassium carbonate solution, dilute hydrochloric acid and barium hydroxide solution Pour all waste liquid into the same clean beaker. What is the final solute in the indicator beaker? I think potassium chloride and barium chloride are possible, but some people say potassium chloride must be. Why?

Explore whether chemical reaction can occur between potassium carbonate solution, dilute hydrochloric acid and barium hydroxide solution Pour all waste liquid into the same clean beaker. What is the final solute in the indicator beaker? I think potassium chloride and barium chloride are possible, but some people say potassium chloride must be. Why?

Barium ions may be completely precipitated by carbonate, so they may not be
There is nothing to consume except potassium and chlorine, so there must be

Hydrogen is prepared from zinc and 2mol / L hydrochloric acid solution in the laboratory. The following measures can reduce the reaction rate () A. Replace zinc block with zinc powder B. Use 1.5mol/l sulfuric acid solution instead C. Use 1mol / L nitric acid solution instead D. An equal volume of water is added to the hydrochloric acid solution

A. Zinc powder replaces zinc block, the contact area increases and the reaction rate accelerates, so a is not selected;
B. Use 1.5mol/l sulfuric acid solution to increase the hydrogen ion concentration and accelerate the reaction rate, so B is not selected;
C. Use 1mol / L nitric acid solution instead, the reaction does not produce hydrogen, so C is not selected;
D. Adding equal volume of water to the hydrochloric acid solution reduces the hydrogen ion concentration and the reaction rate, so D is selected;
Therefore, D

When hydrochloric acid reacts with Zn, why add copper chloride solution in order to speed up the reaction rate? Why?

You're still in junior high school. I tell you you haven't learned that when hydrochloric acid reacts with zinc, adding copper chloride will react with it, and copper will be formed on the surface of zinc, so it will form a primary battery. You knew in high school that the primary battery can speed up the reaction many times. In fact, zinc loses electrons, and the hydrogen ion on copper gets electrons, which become hydrogen, and zinc becomes ions

The following four hydrochloric acid solutions can react with zinc tablets, of which the initial reaction rate is the fastest () A. 3mol / L hydrochloric acid solution at 10 ℃ B. 2mol / L hydrochloric acid solution at 20 ℃ C. 4mol / L hydrochloric acid solution at 10 ℃ D. 4mol / L hydrochloric acid solution at 20 ℃

Factors affecting the chemical reaction rate of roots: the higher the temperature, the faster the reaction rate, so a and C are the slowest; The higher the concentration, the faster the reaction rate, so D is the fastest
Therefore, D

The following four hydrochloric acid solutions can react with zinc tablets, of which the initial reaction rate is the fastest () A. 3mol / L hydrochloric acid solution at 10 ℃ B. 2mol / L hydrochloric acid solution at 20 ℃ C. 4mol / L hydrochloric acid solution at 10 ℃ D. 4mol / L hydrochloric acid solution at 20 ℃

Factors affecting the chemical reaction rate of roots: the higher the temperature, the faster the reaction rate, so a and C are the slowest; The higher the concentration, the faster the reaction rate, so D is the fastest
Therefore, D

At normal temperature, add the following acetic acid solutions of different volumes and concentrations into four beakers containing 10ml and 2mol / LNaOH solutions respectively, and dilute them with water 50ml, of which the highest reaction rate is A.20ml 3mol/l B.25ml.2mol/l C.10ml,3mol/l D,18ml,4mol/l

In fact, the speed of reaction rate depends on the concentration. In this question, D should be selected, because the concentration of acetic acid in D is 4mol. L-1. The greater the concentration, the faster the reaction rate. Just simply compare the following concentrations