High chemical separation problems, high one common methods for separating mixtures

The d option is the most correct :

1.First of all: according to the solubility, barium sulfate is insoluble in water, so after adding water, it will appear in the form of precipitation. Through filtration, barium sulfate can be obtained.

2.Secondly: ferric ions and hydroxide ions react to form iron hydroxide (reddish-brown precipitate), which is precipitated, and the solid and filtrate of iron hydroxide (mixed solution of potassium hydroxide and potassium chloride) can be obtained through filtration

3.Finally, after reduction, hydrochloric acid is added to iron hydroxide to generate ferric chloride, and potassium chloride is generated by adding hydrochloric acid to the filtrate.

There are many ways to separate substances, but when separating with reagents, we must pay attention to: no new impurities can be introduced, even if new impurities are introduced, there must be a way to reduce this new impurities to the original substance, otherwise, this method of removing impurities will fail.

D, BaSO4 is a solid, it can be separated with water, and the premise of separation is not to introduce other ions, so ABC is not allowed, nitrate and sulfate will be introduced.

fecl3+koh--fe(oh)3+koh

Trim yourself.

First of all, A is not right, silver nitrate can not separate iron and potassium, in the remaining 3 answers there are water, potassium hydroxide, these 2 can separate barium and iron, the next thing is to see what acid is used, first after separating barium sulfate with water, there is no sulfate and nitrate ions in the mixture, so BC both answers bring impurities, so the answer is D, it should be noted that there is water in our answer, then potassium hydroxide solution and potassium hydroxide are no different.

Decanting: Separation of dense and insoluble solids from liquids Separation of sand and water filtration: Separation of insoluble solids from liquids Purification of edible water.

Dissolution and filtration: separation of two solids, one is soluble in a solvent, the other is insoluble Separation of salt and sand centrifugal separation method: Separation of insoluble solids from liquid Separation of mud and water crystallization method:

Separation of dissolved solutes from solution Extraction of salt fraction from seawater: separation of two immiscible liquids Separation of oil and water.

Extraction: Add appropriate solvent to dissolve and separate a component in the mixture Use heptane to extract iodine in aqueous solution.

Distillation: separation of solvents and non-volatile solutes from solution Pure water distillation from seawater: separation of two liquids with miscible boiling points Separation of oxygen and nitrogen from liquid air; Petroleum refining.

Sublimation: Separation of two solids, only one of which can be sublimated Separation of iodine and sand adsorption: removal of gaseous or solid impurities in the mixture Removal of colored impurities in brown sugar with activated carbon Chromatography analysis: separation of solutes in solution Separation of substances of different colors in black ink.

Go buy a book like a summary of chemistry knowledge points for the college entrance examination It's very complete There are comparisons I use this kind of book Chemistry basically didn't score 80 Chemistry is mainly to summarize more and memorize more.

Iron finch rot hail powder, sodium hydroxide, thiolic acid sail, 1, Fe + 2Fe3+ = 3Fe2+

fe + cu2+ =cu + fe2+

2、fe2+ +2oh- =fe(oh)23、fe(oh)2 + 2h+ =fe2+ +2h2o

1.The main glass instruments for removing silver chloride (filtration) from salt water are beakers, glass rods, and funnels.

2.The principle of separating Kno3 and NaCl powder (crystallization) is that the solubility of Kno3 varies greatly with temperature, and the solubility of NaCl varies little with temperature.

3.The principle of separating water and alcohol (distillation) is that water first reacts with CaO to form Ca(OH)2, and the boiling point of Ca(OH)2 is much greater than that of alcohol, so it can be distilled.

4.The principle of obtaining iodine from iodine water (extraction) is that the solubility of iodine in CCL4 is much greater than that in water.

5.The principle of separating CCL4 and water (separating) is that Ccl4 and water are not miscible with each other, and the instrument is a separating funnel and beaker.

Strain glass rods, beakers.

Recrystallization The solubility of sodium chloride does not change much with temperature.

Distillation Alcohol volatile Alcohol lamps, flasks, glass rods, beakers, extractions Similar to each other.

Dispensing different densities of separating funnels, beakers, glass rods.

1 funnel. Glass rods. Beaker.

2. The principle is: although the speed of the change of temperature of the two substances is large.

3 fractionation, the boiling point of the two is different, distillation flask, thermometer, condenser tube, horn tube, Erlenmeyer flask, 4 quenching. The degree of resolution of iodine elemental in water varies greatly from that in quenching agents. 5

1. Beaker, glass rod, long-neck funnel.

2. The solubility of NaCl and Kno3 varies with temperature, the solubility of NaCl does not change much with temperature, and the solubility of Kno3 changes greatly with temperature.

3. The boiling point of alcohol and water is different from that of alcohol lamp, distillation flask (long-necked or short-necked round-bottom flask), distillation head, thermometer, condenser tube and horn tube, beaker.

4. The solubility of iodine in carbon tetrachloride is much greater than that in water, and distillation after extraction 5. Ccl4 is incompatible with water Ccl4 is a non-polar molecule, water is a polar molecule, and the two are incompatible.

Liquid: aqueous solution of gasoline and magnesium chloride, because the aqueous solution of gasoline and magnesium chloride is not miscible with each other, and the density of the two hidden liquids is different;

Distillation: 60% alcohol, because the boiling points of alcohol and water are not the same, and alcohol and water can be miscible with each other, so only distillation can be used, (but in general, the separation of boiling points of different liquid mixtures requires the boiling point difference of more than 30 between the boiling points of the two liquids).

Extraction: Aqueous solution of sodium chloride and elemental bromine. Because sodium chloride is soluble in water and not soluble in organic solvents (e.g., carbon tetrachloride), bromine is soluble in organic residue solvents and not soluble in water, and organic solvents and water are not miscible with each other, so they can be separated by extraction.

Oily substances and aqueous substances (insoluble stratification) are separated with liquid, and salt is generally water-based and soluble in water, so it often converts an organic substance into a salt that is easily soluble in water and splits the collision layer, in addition, adding inorganic salts can reduce the solubility of organic matter with complex structure in water to search for dust, which is called salting-out; 1. Phenol is weakly acidic, so first add sodium hydroxide to become sodium phenol, which is soluble in water, and can be stratified with benzene and separated.

2. Alcohol and water distillation will form azeotrope and steam out together, so add quicklime and water to react into calcium hydroxide with high boiling point, and then evaporate the alcohol.

3. Acetic acid reacts with sodium carbonate to form sodium acetate that is easily soluble in water, and at the same time, due to salting out, saturated sodium carbonate can reduce the solubility of ethyl acetate in water, and the stratification is more obvious, and the liquid is separated.

4. Add sodium chloride first to reduce the solubility of soap in water (analogous to protein salting-out), glycerol is easily soluble in water, and the soap is filtered out.

Filtration to remove sludge, (2).

Excess iron powder is added to the filtrate to make AG

reduced to metallic silver, (3).

(4) the ag mixed with iron powder is treated with dilute sulfuric acid to dissolve fe, (5) the hail cherry is filtered to separate the silver, and (6).

The filtrates in steps (3) and (5) were combined, evaporated and concentrated, and cooled to crystallize ferrous sulfate and precipitate (7).

Filtered to obtain ferrous sulfate crystals, Na

Leave in the mother liquor. Split Hall.