What is the color of the residue and filtrate on the filter paper when filtered in coarse salt purif

Coarse salt contains insoluble impurities such as sediment, as well as soluble impurities such as Ca2+, Mg2+, SO42-, etc.

1. Experimental Procedure:

1. Measure 10ml of water with a graduated cylinder and pour it into a beaker. Add coarse salt to the water with a medicine spoon and stir with a glass rod to observe the phenomenon. Then add the coarse salt and stir with a glass rod until the coarse salt is no longer dissolved. Observe if the solution becomes cloudy.

2. Add excess BACL2 (remove sulfate ions) BAC2 + Na2SO4 ==BASO4 +2NaCl

3. Add excess NaOH (remove magnesium ions) MgCl2 + 2NaOH = = Mg(OH)2 + 2NaCl

4. Add excess Na2CO3 (remove calcium ions and barium ions in BaCl2) Na2CO3 + CaCl2==CaCO3 + 2NaCl

5、 na2co3+bacl2==baco3↓+2nacl

6. Filtration. Add an appropriate amount of HCl to the filtrate (remove excess NaOH and Na2CO3, you can choose to control the amount with pH test paper, or evaporate directly).

7.Evaporation crystallization.

2. Experimental phenomena:

1. Dissolution: The coarse salt solid is gray, and the liquid obtained by adding water is turbid.

2. Filtration: The filtrate is a colorless and transparent liquid, and the residue on the filter paper is black.

3. Evaporation: With heating, the amount of liquid in the evaporation dish decreases; When evaporation reaches a certain level, there is a precipitation of solids from the bottom of the evaporation dish. The solids obtained by evaporation are white.

3. Experimental conclusions.

In coarse salt purification, the residues on the filter paper during filtration are BaSO4, Mg(OH)2, CaCO3 and sediment. The filtrate is colorless and transparent.

Depending on what kind of coarse salt you are, the textbook is coarse salt mixed with sand, and the filter paper may be yellow, and the filtrate is colorless.

Summary. First, excess NaOH solution and Na2CO3 solution were added to the refined salt solution to convert Mg2+ and Ca2+ into Mg (OH) 2 and CaCO3 precipitate.

Firstly, the excess NaOH solution and Na2CO3 solution were added to the refined salt solution, and the Mg2+ and Ca2+ were transformed into Mg(OH) 2 and CaCO3 precipitation.

The first time is impurities.

The second is to generate a precipitate and remove it, which can also be removed by adding BaCO3 solid and NaOH solution.

Firstly, the excess NaOH solution and Na2CO3 solution were added to the refined salt solution, and the Mg2+ and Ca2+ were transformed into Mg(OH) 2 and CaCO3 precipitation.

This is the third time.

What is the purpose of adding HCl to coarse salt purification?

Balance acidity and base. and NaOH reaction.

What is the yield of pure cotton NaCl in coarse salt purification.

What is the yield of pure NaCl in crude salt purification.

Yield = pure NaCl saline weight.

Yield = pure NaCl coarse salt.

Coarse salt quality. Generally 80% 90%.

Small: the amount of water poured is insufficient when dissolved, and the sodium chloride is only partially dissolved; Liquid spills when dissolved; Failure to drain with glass rods during filtration leads to liquid spillage; When filtering, the beaker is removed without waiting for all the filtrate to flow into the beaker; Heating stops when evaporation dries; When evaporating, the glass rod is not stirred, and the local overheating causes the droplets to splash.

Large: "left yard and right object" when weighing the quality of coarse salt; When dissolving, salt water is used instead of distilled water; During filtration, the filter paper leaked, and some of the sediment entered the beaker.

After folding the filter paper, moisten it with a glass rod dipped in water to make it close to the inner wall of the funnel and bring a plum to make the upper edge of the filter paper lower than the mouth of the funnel, and the liquid level of the solution is lower than the upper edge of the filter paper, and the mouth of the beaker where the liquid is poured should be close to the glass rod, the end of the glass rod is close to the side with three layers of filter paper, and the end of the funnel is close to the inner wall of the beaker containing the filtrate.

Pour the liquid slowly, and when there is no water in the filter paper, carefully observe the residue on the filter paper and the color of the filtrate. When the filtrate is still cloudy, it should be filtered again.

Hello. According to your description, the breakage of the filter paper can cause large salt particles to enter the filter billowing permeate Beikai, resulting in a high concentration of the sodium chloride solution. Hope it helps.

Summary. Hello, because of this, coarse salt generally contains calcium chloride and magnesium chloride impurities, so the coarse salt is fully dissolved in water and then added to the excess sodium carbonate solution, after filtering out the precipitation of calcium carbonate and magnesium carbonate, there are newly introduced carbonate ions in the solution, as long as excessive dilute hydrochloric acid is added until carbon dioxide bubbles no longer emerge, and finally the solution is poured into the evaporation dish for heating, the excess hydrochloric acid will volatilize into the air, so that the obtained will be relatively pure salt.

Hello, because of this, coarse salt generally contains calcium chloride and magnesium chloride impurities, so the coarse salt is fully dissolved in water and then added to the excess sodium carbonate solution, after filtering out the precipitation of calcium carbonate and magnesium carbonate, there are newly introduced carbonate ions in the solution, as long as excessive dilute hydrochloric acid is added until carbon dioxide bubbles no longer emerge, and finally the solution is poured into the evaporation dish for heating, the excess hydrochloric acid will volatilize into the air, so that the obtained will be relatively pure salt.

Hello, no. Because coarse salt generally contains impurities of calcium chloride and magnesium chloride, the coarse salt is fully dissolved in water and then an excess sodium carbonate solution is added, and after the calcium carbonate and magnesium carbonate are precipitated, there are newly introduced carbonate ions in the solution, as long as excessive dilute hydrochloric acid is added until carbon dioxide bubbles no longer emerge, and finally the solution is poured into the evaporation dish for heating, and the excess hydrochloric acid will volatilize into the air, so that the obtained salt will be relatively pure.

Coarse salt contains impurities such as MgCl2, CaCl2, MgSO4 and sediment (1) Add BaCl2 to remove SO42- to generate Baso4 precipitate (2) Add NaOH to remove MgCl2 to generate Mg(OH)2 precipitate (3) Add Na2CO3 to remove excess BaCl2 and CaCl2 (4) filtration.

5) Add an appropriate amount of dilute hydrochloric acid to the filtrate to remove sodium hydroxide and sodium carbonate, and finally, concentrate to obtain pure NaCl

Experimental Procedure Experimental Phenomenon Explanation or Conclusion.

1. Dissolve: Take about 12 ml of water with a graduated cylinder and pour it into a beaker. Weigh about 6 g of coarse salt on a tray balance.

Gradually add the weighed kosher salt to the water in the beaker and stir constantly with a glass rod until the kosher salt is no longer dissolved. Weigh the remaining coarse salt. Coarse salt solids are colored.

The liquid obtained by adding water is in the form of a state. The remaining coarse salt is g. Coarse salt contains other impurities.

Dissolve about g of coarse salt in 12 ml of water.

2. Filtration: Make a filter with filter paper and funnel. Filter the liquid from the beaker by pouring it down the glass rod into the strainer.

If the filtrate is still cloudy, it should be filtered again. Filter the signs of success. The filtrate is a colored liquid, and the residue on the filter paper is a colored one.

The main components of the filtrate are: The coarse salt is insoluble in water and is left on the filter paper to be separated. Filtration can remove coarse brine.

3. Evaporation: Put the evaporation dish on the iron ring of the iron frame, pour the filtrate into the evaporation dish, heat it with an alcohol lamp, and constantly stir the liquid with a glass rod, and stop heating when there are more solids. With heating, the amount of liquid in the evaporation dish ; When the evaporation reaches a certain level, there is precipitation at the bottom of the evaporation dish.

The solid obtained by evaporation is colored. If there is a splash of liquid or solid during the heating process, the cause is . The main ingredient to get a solid is .

4. Weighing: After the solid in the evaporation dish is cooled to room temperature, the solid mass is weighed. The solid mass is g. The yield of refined salt is %.