Senior one chemistry difficult , advanced masters, high one chemistry problems

Select C to generate Al(OH)3 precipitates.

Al2(SO4)3 reacts with soda ash solution, and trivalent aluminum ions will be double-hydrolyzed with carbonate ions to form trivalent hydroxide precipitate and carbon dioxide gas.

Al2(SO4)3 reacts with sodium sulfide to form Al2S3, and Al2S3 dissolves in water to undergo mutually promoting hydrolysis, the so-called double hydrolysis. al2s3+6h2o=3h2s↑+2al(oh)3 ↓.

Exclusion can also be used.

a. with caustic soda solution to form AG2O; The product with the soda ash solution is absent; Silver sulfide is formed with sodium sulfide;

b with caustic soda solution to form Fe(OH)3 precipitate; Ferrite will be double hydrolyzed with CO3; It undergoes a redox reaction with sodium sulfide to form elemental sulfur and ferrous hydroxide, which is then oxidized to iron hydroxide.

d with caustic soda solution to generate Cu(OH)2 precipitate; with soda ash solution to form copper carbonate; with sodium sulfide to form a cus precipitate.

Select C to generate Al(OH)3 precipitates.

Al2(SO4)3 reacts with soda ash solution to form alumina, which is a substance that will decompose rapidly when exposed to water, because trivalent aluminum ions will be double hydrolyzed with carbonate ions to generate trivalent hydroxide precipitation and carbon dioxide gas.

Al2(SO4)3 reacts with sodium sulfide to form Al2S3, and Al2S3 dissolves in water to undergo mutually promoting hydrolysis, the so-called double hydrolysis. al2s3+6h2o=3h2s↑+2al(oh)3 ↓

Therefore, C is chosen

is cal3+ +3oh-==al(oh)3 3CO32- +2al3+ +3h2o=2al(oh)3 +3CO2

Although al3+ +s2-==al2s3

However, Al2S3 is easily hydrolyzed into Al(Oh)3 and H2S

The selection of Cal2(SO4)3 will form Al(OH)3 precipitate with all three solutions.

A and caustic soda solution to form Agoh (will become Ag2O), and sodium sulfide to form silver sulfide;

b with caustic soda solution to form Fe(OH)3 precipitate, with sodium sulfide redox reaction;

d with caustic soda solution to generate Cu(OH)2 precipitate, with sodium sulfide to generate Cus precipitate.

Choose C, because the three solutions are alkaline solutions, so they all generate aluminum hydroxide precipitates.

The answer is cExplanation: AThe three precipitates are Ag2O (silver oxide), Ag2CO3 (silver carbonate), and Ag2S (silver sulfide).

b.The precipitates are Fe(OH)3, Fe2CO3, Fe(OH)3 (due to Fe3+ and S2- double hydrolysis), respectively

c.All three precipitates are Al(OH)3, the last two of which are produced due to double hydrolysis.

d.The precipitation is Cu(OH)2, CuCO3, Cus (the latter two will not be hydrolyzed, insoluble in water, you can turn the acid-base salt solubility table yourself).

c "Add an appropriate amount separately"Al2(SO4)3 reacts with caustic soda solution, and if it is excessive, the precipitate disappears.

Since it's a multiple-choice question, you can substitute it for exclusion.

Summary. The third question, add hydrochloric acid acidified barium chloride solution, if there is a white precipitate, there are sulfate ions, on the contrary, there are none.

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How many questions are asked, dear.

Question 2, Question 3.

Good. The second question, the law of redox reaction, the valence of the valence is conserved, there must be a rise, there must be a fall, and the price of sulfur elemental to sulfite must fall, then there are sulfur ions.

The third question, add hydrochloric acid acidified barium chloride solution, if there is a white precipitate, there are sulfate ions, on the contrary, there are none.

Answer: c

Analysis: A: False, dilute nitric acid has strong oxidation and will not react with zinc to form H2, and metal and nitric acid will not react with H2 to form.

B: False, adding dilute sulfuric acid dropwise to saturated salt water will not produce HCl, and concentrated sulfuric acid can be added dropwise like NaCl solid to prepare HCl

C: Correct. D: The calcium sulfate generated by the reaction between marble and concentrated sulfuric acid will cover the surface of the marble and prevent the reaction, so it cannot be used to prepare CO2, nor can dilute sulfuric acid, for the same reason.

There may be no and no 2 in the reaction in b a

By-products may be produced in c.

d. Medium strong sulfuric acid is changed to dilute hydrochloric acid.

ca can't make h2, only no

b If HCI cannot be prepared, solid sodium chloride and concentrated sulfuric acid need to be co-heated.

d As I said in junior high school, calcium sulfate is slightly soluble and covers calcium carbonate to prevent the reaction from continuing.

Option nitric acid has strong oxidizing properties and produces water. Item b does not respond. Item C is known according to the strong acid to the weak acid. Sulfuric acid cannot be used in item d, because the reaction produces slightly soluble calcium sulfate that adheres to its surface and will stop the reaction.

Hydrogen production does not use dilute nitric acid, it is oxidizing.

b, does not react.

Item d, concentrated sulfuric acid is oxidizing.

Choose C answer.

A false. Zinc reacts with dilute nitric acid to produce zinc nitrate that releases nitric oxide. Because concentrated and dilute nitric acid is oxidizing. Irrationality.

b False. The resulting HCl is highly soluble in water and cannot be collected.

c Right. Sulfur dioxide is made in the laboratory, using sodium sulfite to react with 70% concentrated sulfuric acid. Calcium sulfate is also generated, which has a small content and carbon dioxide is not easy to release. Not practical.

For example: Na2SO3 + H2SO4 = Na2SO4 + H2O + SO2

And because it is concentrated sulfuric acid, the reaction solution will absorb less SO2.

The nitric acid in item A has strong oxidation regardless of concentration or diluteness, and cannot produce hydrogen with zinc particles, but can only produce water, and item B dilutes sulfuric acid and HCl

Both are strong acids, which do not conform to the rules of strong acids to weak acids, and the two do not react; C term Na2SO3 + H2SO4 = Na2SO4 + H2O + SO2 and because it is concentrated sulfuric acid, the absorption of SO2 by the reaction solution will be relatively small; Item D marble does not react with concentrated sulfuric acid. Therefore, C