A chemical problem about testing for impurities !!

1. Reasonable When the mixed gas of oxygen and carbon monoxide is passed through the hot copper oxide, because copper oxide is oxidizing and carbon monoxide is reducing, the two can react with oxygen. Copper and carbon dioxide are generated, and the oxygen in the mixed gas does not participate in the reaction, it still exists in the form of oxygen, at this time, the mixed gas has no carbon monoxide, but becomes a mixture of oxygen and carbon dioxide, when the mixed gas is passed into the clarified lime water, due to the presence of carbon dioxide, it can be observed that the clarified lime water becomes turbid. Therefore, this test method is reasonable.

2 is unreasonable, because concentrated sulfuric acid is used to remove water in the mixed gas, not to verify the presence of water, the best substance to verify the existence of water is anhydrous copper sulfate, when it encounters moisture, it will change from colorless to blue. As mentioned in the title, when the mixed gas of water and carbon dioxide passes into anhydrous copper sulfate, the water reacts with anhydrous copper sulfate, so that the anhydrous copper sulfate is covered with crystalline water and turns blue. At this point, only carbon dioxide gas remains, and when it passes through the clarified lime water, it can be observed that the lime water becomes turbid.

Therefore, 2 is unreasonable, and concentrated sulfuric acid should be replaced with anhydrous copper sulfate.

It should also be noted that it should be passed through anhydrous copper sulfate first, and then through the clarified lime water, if the position is mixed, it is not known whether the cause of the discoloration of anhydrous copper sulfate is the original water in the mixed gas, or the water brought out when the lime water is clarified first.

Hope it helps.

1. Unreasonable, there may also be CO2 in O2

2. It should be considered okay to test the weight gain of concentrated sulfuric acid. However, I think it is more intuitive to pass the anhydrous copper sulfate test water, white to blue.

1. Unreasonable, although CO can make copper oxide red, but at the same time, oxygen oxidizes the reduced copper into copper oxide, and there is more oxygen, a small amount of CO, and there is no phenomenon.

2. Reasonable, concentrated sulfuric acid can absorb water, weight gain can be measured, clarified lime water absorbs CO2 to produce white precipitation, now it is obvious that although concentrated sulfuric acid has strong oxidation, but does not oxidize CO, so it can.

If water and carbon dioxide are passed together through anhydrous copper sulfate, basic copper sulfate will be produced, so anhydrous copper sulfate cannot be used, color-changing silica gel should be used, and there will be no side reactions.

3. No, HCl, CO2 and silver nitrate react to form silver oxide precipitate, so no.

1.Plausible. CO is reducible, and Cuo can be used to displace Cu and generate carbon dioxide, so by clarifying lime water, lime water will become turbid. It can be proven that oxygen contains carbon monoxide.

2.Irrationality. Concentrated sulfuric acid has the function of drying, can dry part of the gas, but to test the existence of water, to use anhydrous copper sulfate, after passing, anhydrous copper sulfate turns blue, through the clarification of lime water, lime water becomes turbid, can prove the existence of carbon dioxide.

1) Unreasonable, may or contain carbon dioxide should be first clarified lime water, then through calcination copper oxide, and then through clarified lime water, to ensure that there is no carbon dioxide in the gas through copper oxide.

2) Unreasonable, concentrated sulfuric acid is easy to oxidize CO to carbon dioxide, so it is not certain whether there is carbon dioxide. Anhydrous copper sulphate should be passed first, and then through clarified lime water.

Is it reasonable to test HCL and CO2 in H2 through silver nitrate solution and clarified lime water? Why?

Plausible.

Irrationality.

CO is flammable, burns with O2, and is not pure!!

Insecurity!! Unreasonable Concentrated sulfuric acid can absorb water vapor, but can not prove the existence of water vapor!!

Irrationality. Because CO2 also forms a white precipitated Ag2CO3 with silver nitrate, it interferes with the identification of HC!!

Hope I was chosen with the correct answer, thank you.

1) Unreasonable, it is necessary to use clarified lime water to detect that there is no CO2, and to use scorching copper oxide.

2) It is unreasonable to use anhydrous copper sulfate, because concentrated sulfuric acid can only absorb water, and cannot reflect whether there is water.

v unreasonable, to burn copper oxide.

It should be copper oxide, not oxidizing. It is necessary to burn copper oxide to have strong oxidation and unreasonable concentrated sulfuric acid has strong oxidation. It is not reasonable to oxidize CO to CO2... There is no noticeable change from HCl to silver nitrate solution.

It's not reasonable... Lime water first.

2 is not too outrageous...

Remove CO2 from hydrogen and pass it into the caustic soda solution 2NaOH+CO2=Na2CO3+H2O

What's in calcium carbonate?

The second question is that CA is evaporated and crystallized.

b is still a saturated solution, the water and salt that go out are saturated, and the rest is also.

d does not decompose.

The upstairs of calcium carbonate is said to use 4 water, and hydrogen is used with 1

23 Can't be used, what do you want to remove with them? I'll explain.

Sodium sulfate and hydrochloric acid are not reactive with CO2.

Hydrochloric acid will react the calcium carbonate away, and it will not be able to remove impurities.

Sodium sulfate can't be used to remove sodium carbonate.

1: (1) CaCO3 is insoluble in water, Na2CO3 is soluble, add water to dissolve, and filter it.

2) CO2+2NaOH====Na2CO3+H2O hydrogen and sodium carbonate solution do not react.

2: C has nothing to say, the fact is that, B gets a saturated solution, and only when it is saturated and then evaporates the water through the sun will the crystals be precipitated.

1) Fill in the code of the selected reagent on the corresponding horizontal line

CaCO3 powder (Na2CO3).

h2（co2）

2) Write the chemical equation about the reaction: CO2+2NaOH=Na2CO3+H2O Solution: (1) Both substances are carbonates, so sodium carbonate cannot be removed from hydrochloric acid in the optional reagent; Carbonic acid cannot react with caustic soda solution or sodium sulfate solution, so these two reagents cannot be used to remove sodium carbonate; Therefore, the water in the reagent is selected to remove the soluble sodium carbonate from the calcium carbonate that is insoluble in water;

So the answer is: ;

Carbon dioxide can produce sodium carbonate and water with caustic soda solution, while hydrogen cannot react with this solution, so caustic soda solution can be used to absorb carbon dioxide gas mixed in hydrogen;

So the answer is: ;

In the above impurity removal process, only carbon dioxide reacts with caustic soda solution (sodium hydroxide solution) to produce sodium carbonate and water;

Therefore, choose CO2 + 2NaOH = Na2CO3 + H2O (write CO2 + NaOH = NaHCO3 and also give points).

In the first question, the parentheses are NAC3, CAC3 is precipitate, and NAC3 is soluble; The second question: CO2 can react with caustic soda solution: CO2 + NaOH = NaCO3 + H2O

1.Dilute sulfuric acid is added and filtered. cuo+h2so4=cuso4+h2o

2.Dilute sulfuric acid is added and filtered. fe2o3+3h2so4=fe2(so4)3+3h2o

3.Pyrolysis. CaCO3 = High temperature = Cao + CO2

4.After passing through the NaOH solution, it is dried with concentrated sulfuric acid. hcl+naoh=nacl+h2o

5.Through saturated NaHCO3 solution. hcl+nahco3=nacl+h2o+co2↑

6.After passing through the NaOH solution, it is dried with concentrated sulfuric acid. co2+2naoh=na2co3+h2o

7.through the scorching copper oxide. Cuo + Co = High Temperature = Cu + CO2

Cu[cuo] dilute hydrochloric acid.

C[Fe2O3] dilute hydrochloric acid.

CAO[CACO3] heats solids.

H2[HCl] zinc tablets.

CO2[HCl] limestone.

CO[CO2] clarified lime water.

CO2[Co] Heated copper oxide.

1. Add bacl2 until the precipitate is no longer generated, and filter the beat. Precipitated to BaSO4, SO4 ions were removed and BA ions were introduced.

2. NaOH is added to generate Mg(OH2) precipitate, filtered, and the differential bond removes MG ions, and OH- ions are introduced.

3. Add excess Na2CO3 to generate a precipitate, filter, and go out of Ca, Ba ions. CO3 is introduced.

4. Add an appropriate amount of HCl to remove CO3 ions and neutralize OH- ions.

The answer is D.

The basic principle of impurity removal: the original substance does not react with additives; The addition of additives is easy to separate from the original substance after reacting with impurities.

A: Phenol can react with bromine water to form tribromophenol, which is soluble in benzene. Separation is not possible.

B: Ethylene reacts with acidic potassium permanganate to obtain CO2 gas, and methane is also a gas. The purpose of separation was not achieved.

C: Ethyl acetate undergoes hydrolysis reaction with NaOH solution (consumption of the original substance) D: H2S can form Cus precipitate with Cu2+. Therefore, H2S can be removed to obtain a purer acetylene. (Ignoring the reaction of acetylene copper in high school).

Hope it helps

If you have any doubts, please feel free to ask.

Obviously, phenol and benzene are dissolved in bromine water, ethylene produces CO2 in KMno4, and the heart impurity C ethyl acetate is decomposed in sodium hydroxide solution.

A: Ca(OH)2 absorbs CO2

B: Feasible. C: O2 is more oxidizing than Cuo, and under heating conditions, it is definitely oxygen that preferentially reacts with CO.

D: CO has reducibility, concentrated sulfuric acid has strong oxidation, and it must be incompatible with water and fire to react.

That last sentence is true, nothing is absolute. However, in practice, residual moisture is negligible.

I did choose B because of the same floor.

The last sentence is ambiguous, to be exact.

When evaporating, it is not possible to completely evaporate the water in the mixture.

Reagent equation.

NaHCO solution (Na2CO3) H2O, CO2 CO3 2-+CO2+H2O===2HCO3-

fe203(al2o3) naoh ai2o3+2oh-==2aio2-+h2o

FeCl3 solution (FeCl2) Ci2 2Fe2+ + Ci2===2Fe3+

co2(hcl) nahco3 hci+hco3-==ci- +co2+h2o

Hope, thank you!

1. Pass CO2

2, NaOH solution.

3, pass CL2

4. Pass in baking soda solution.

To remove H2SO4 in HCL, the essence is to remove sulfate ions, H2SO4 can be used to react with barium chloride solution to generate barium sulfate lake and hydrochloric acid, and then filtered, impurities can be removed and no new impurities are introduced, in line with the principle of impurity removal, the chemical equation of the reaction is: H2SO4 + BACl2 = BaSO4 + 2HCl

To remove Na2CO3 in NaCl solution, the essence is to remove carbonate ions, sodium carbonate solution can be used to react with an appropriate amount of dilute hydrochloric acid to generate sodium chloride, water and carbon dioxide, which can remove impurities and no new impurities are introduced, in line with the principle of impurity removal, the chemical equation of the reaction is: Na2CO3 + 2HCl 2NaCl + H2O + CO2 (reasonable).

According to the order of metal activity, iron can react with acid, copper and acid do not react, so iron can be removed with hydrochloric acid or dilute sulfuric acid, and then filtered, impurities can be removed and no new impurities are introduced, in line with the principle of impurity removal, the chemical equation of the reaction is: Fe + 2HCL = FeCl2 + H2

Cuo can react with dilute sulfuric acid to generate copper sulfate and water, copper does not react with dilute sulfuric acid, can remove impurities and does not introduce new impurities, in line with the principle of impurity removal, the chemical equation of the reaction is: H2SO4 + Cuo CuSO4 + H2O

Therefore, the answer is: impurity removal reagent.

Chemical equation.

HCl (H2SO4) solution.

Barium chloride solution.

h2so4+bacl2=baso4↓+2hcl

NaCl (Na2CO3) solution.

Dilute hydrochloric acid Na2CO3+2HCl2NaCl+H2O+CO2

Cu (Fe) solid.

Fe hydrochloride + 2HCl = FeCl2 + H2

Cu (cuo) solid.

Dilute sulfuric acid H2SO4 + Cuo CuSO4 + H2O

Substance Impurities The reagent (or method) selected to remove impurities

H2 water vapor concentrated sulfuric acid.

H2 CO2 soda lime.

Cu Zn is fully reacted with dilute sulfuric acid and filtered.

Fe ZN ferrous sulfate solution.

Cao CaCO3 pyrolysis.

FeCl3 HCl iron oxide.

Na2SO4 Na2CO3 dilute sulfuric acid.

NaOH Na2CO3 calcium hydroxide solution.

NaCl MgSO4 barium hydroxide solution.

nano3 cuso4 barium hydroxide solution.

NaCl MgCl2, CuCl sodium hydroxide solution.

Na2SO4 NaOH, Na2CO3 dilute sulfuric acid.