The basic properties of concentrated Hcl solution, how to ensure the safety of operation

Concentrated hydrochloric acid: hydrochloric acid with a mass fraction of more than 20%.

It is volatile, colorless, transparent and has a white haze, and is chemically acidic.

Strongly acidic, and should also be oxidizing.

Hydrochloric acid with a mass fraction of more than 20% is called concentrated hydrochloric acid. The concentration of commercially available concentrated hydrochloric acid is 36% 38%, and the concentration of concentrated hydrochloric acid for experimental use is generally 36% 38%, and the concentration of the substance: 12mol l.

density, is an azeotropic mixture. Concentrated hydrochloric acid is highly volatile in the air and has strong corrosiveness to ** and clothing. Concentrated hydrochloric acid reacts to produce chlorine gas, chloride, and water.

Hydrochloric acid (hydrochloric acid, aqueous solution of HCl gas, colorless liquid) Concentrated hydrochloric acid is volatile and volatilizes HCl

Acids, hydrochloric acid, sulfuric acid.

Physical properties Volatile Produces white mist in the air Concentrated sulfuric acid is water absorbent.

Chemistry. The method of proving to be an acid litmus litmus solution when it meets hydrochloric acid: turns red litmus solution when it meets sulfuric acid: turns red.

Colorless phenolphthalein in case of hydrochloric acid: does not change color Colorless phenolphthalein in case of sulfuric acid: does not change color.

Reacts with the metal Zn +2HCl=ZnCl2+H2

fe+2hcl=fecl2+h2↑ zn +h2so4=znso4+h2↑

fe +h2so4=feso4+h2↑

with metal oxides.

Reaction Iron oxide.

The solid dissolves and the solution turns yellow The solid dissolves and the solution turns yellow.

fe2o3+6hcl=2fecl3+3h2o fe2o3+ 3h2so4= fe2（so4）3+3h2o

Copper oxide The solid dissolves, and the solution changes from colorless to blue The solid dissolves, and the solution changes from colorless to blue.

The equation phenomenon that reacts with the alkali hydrogen and oxygen.

Iron dissolves the solid and the solution turns yellow The solid dissolves and the solution turns yellow.

Copper hydroxide. The solid dissolves and the solution changes from colorless to blue The solid dissolves, and the solution changes from colorless to blue.

Reacts with carbonate sodium carbonate.

Calcium carbonate test CL, SO42 method CL: add silver nitrate solution, and then add nitrate SO42:

Phenomenon There is a white precipitate insoluble in nitric acid and a white precipitate insoluble in nitric acid.

Equation: Nitric acid must be added to dilute such reactions to eliminate the influence of CO32- and OH- on the experiment.

The difference between hydrochloric acid (or chloride) and sulfuric acid (sulfate): it is best to use barium chloride (barium nitrate or barium hydroxide), a compound of soluble barium, with a white precipitate to produce sulfuric acid (sulfate), and no phenomenon is hydrochloric acid.

Silver nitrate solution cannot be used, because silver nitrate reacts with sulfuric acid and silver sulfate white precipitate to form.

What are the properties of hydrochloric acid and sulfuric acid.

Concentrated hydrochloric acid: hydrochloric acid with a mass fraction of more than 20%.

Volatile, acidic, decomposes by heat and releases HCl gas.

Strongly acidic, reducing, oxidizing. Volatilization.

EDTA molecular weight.

However, it is generally used as a disodium salt.

Approximately 336 grams are soluble in water.

Approachable because EDTA needs to be calibrated before it can be used.

It cannot be formulated directly.

Follow the quality you take.

The result of the calibration should be less than.

In practice.

The concentration will be much smaller.

Depending on the need, there are many concentrations of hydrochloric acid standard solutions, and the commonly used ones are.

The percentage concentration is 38%, the density is grams of cubic centimeters of concentrated HCl HCL, 1000 ml of this concentrated HCL contains HCl mass = 1000 g 38% = grams of HCL molar mass is, the molar concentration of this concentrated HCL =

The unit of molar concentration is mol l, which is abbreviated as m.

1000ml/11. 40mol=87.72ml of 1mol, measure the ml of concentrated hydrochloric acid in a 1000 ml volumetric flask, add water to the scale, uniformly, and its concentration is 1m.

In the last step of the volumetric flask, add water first, and then add hydrochloric acid, otherwise it will boil.

A bottle of 36% concentrated hydrochloric acid, prepare a 1mol l solution of hydrochloric acid as follows:

1. When preparing the solution, the practice taken in the high school stage should be to calculate the volume of concentrated hydrochloric acid required according to the volume of the solution to be prepared, and use a volumetric flask to prepare.

For example, if you want to prepare 500ml, 1mol l dilute hydrochloric acid with 36% hydrochloric acid, first calculate the volume of concentrated hydrochloric acid required, and the process is as follows:

The solution yields v=43ml

2. Take 43ml of 36% hydrochloric acid with a graduated cylinder and pour it into the beaker, dissolve it with distilled water, drain it with a glass rod and inject it into a 500ml volumetric flask, wash the beaker and glass rod 2 to three times, and the washing liquid should also be drained into the volumetric flask, then add water to the volumetric flask to 1 to 2 cm away from the scale mark, use a rubber head dropper to add dropwise until the liquid level is level with the scale line, cover the stopper and shake well, and put it into the reagent bottle.

Concentrated hydrochloric acid is required initially.

The concentration can give the preparation method.

Assuming that it is 36% 38% concentrated hydrochloric acid, the concentration can be calculated as mol l, and the method of preparing 1mol l of hydrochloric acid solution is to take about 98ml of concentrated hydrochloric acid to 1 l.

How do you make one mole of hydrochloric acid per liter with concentrated hydrochloric acid? The specific operation process is answered in the laboratory operation.

Dilute it to this concentration with water in concentrated hydrochloric acid.

Operation steps: 1. Inject 9ml of concentrated hydrochloric acid with a concentration of 36 to 37%.

2. Inject 1000ml of water.

3. Shake well to mix concentrated hydrochloric acid with water.

4. Closed storage.

5. Complete the configuration.

To prepare 1 liter of dilute hydrochloric acid, a volume of 12mol l of concentrated hydrochloric acid is required, 1000 ml.

That is, take a milliliter of concentrated hydrochloric acid and dilute it with water to a liter of solution.

Generally, the mass fraction of concentrated hydrochloric acid on the market is 36%-38%, taking the content of 37% as an example, its density is, the molar number of 1L concentrated hydrochloric acid is 37%* (the molar concentration is 12mol L. Now to configure 1M hydrochloric acid, it is necessary to configure 1mol L hydrochloric acid, according to the formula C1 * V1 = C2 * V2, 12 * 1 = 1 * V to obtain V 12L, V = V (concentrated hydrochloric acid) + V (water), so V (concentrated hydrochloric acid) 1L, V (water) 11L, which means that 1L of concentrated hydrochloric acid is added to 11L of water to dilute the dilute dilute of dilute dilute the dilute hydrochloric acid, its concentration is 1mol L, how much 1M hydrochloric acid to use, according to the corresponding proportion.

1. React with acid-base indicator, the purple litmus test solution turns red when it encounters acid, and the colorless phenolphthalein test solution does not change color when it encounters acid, pH 7.

2. Metal acid salt H2 before hydrogen (Note: concentrated sulfuric acid and nitric acid do not react with metal to generate hydrogen, but to generate water).

3. Hydrochloric acid, alkaline oxide, brine water.

4. Hydrochloric acid and alkali undergo a neutralization reaction to produce salt and water: acid-alkali brine ("neutralization reaction").

5. Hydrochloric acid salt, new acid, new salt.

Chemical properties of salts in junior high school chemistry experiments.

Samples were taken and dropped into barium chloride solution, and the precipitate was concentrated sulfuric acid (the precipitate was barium sulfate), and the non-precipitated was concentrated hydrochloric acid.

The sample is dropped on the white paper, and if the white paper is dehydrated and blackened, it is concentrated sulfuric acid.

When the liquid is injected into the water separately, it is concentrated sulfuric acid that will be exothermic.

1.Method 1: Take advantage of the difference in physical properties between the two

Due to the relatively large density of concentrated sulfuric acid, it is viscous. Just pick up the reagent bottle and shake it, and the concentrated sulfuric acid will be there"Wall-mounted"The phenomenon that sticks to the wall of the reagent bottle is not easy to come down, and it is easy to see its viscosity. So, shake the reagent bottle, there is"Wall-mounted"The phenomenon is concentrated sulfuric acid, none"Wall-mounted"The phenomenon is concentrated hydrochloric acid.

2.Method 2: Take advantage of the difference in chemical properties between the two

Concentrated sulfuric acid is known to be strongly corrosive, but unlike concentrated hydrochloric acid, its corrosiveness manifests itself as dehydration. It can rob paper, wood, cloth, ** (all composed of compounds containing carbon, hydrogen, oxygen and other elements) to produce black charcoal. Therefore, you can take a small amount of drops on paper, cloth, etc., the paper or cloth carbonized and blackened is concentrated sulfuric acid, and there is no obvious change is concentrated hydrochloric acid.

3.Method 3: Take advantage of the difference in chemical properties between the two

The chemical properties of concentrated hydrochloric acid and concentrated sulfuric acid are very similar because they both contain hydrogen ions and both belong to the group of acids. But the difference is their acid ions, one is chloride and the other is sulfate. Sulfate ions can combine with barium ions to form barium sulfate precipitates, while chloride ions cannot.

Therefore, take a small amount of each in the test tube, add a small amount of water to prepare a dilute solution, and add barium chloride solution (BaCl2) dropwise to it, the original white precipitate is concentrated sulfuric acid (BaCl2 + H2SO4 ==BaSO4 +2HCl), and the original is concentrated hydrochloric acid without obvious phenomenon.

1. Observation method, concentrated sulfuric acid is very viscous.

2 Or the observation method, open the lid, the concentrated hydrochloric acid will emit white smoke.

3. Dilute with water, and concentrate sulfuric acid to release a lot of heat.

Concentrated hydrochloric acid is yellow, concentrated sulfuric acid is colorless, viscous, oily liquid.