Лаборатория иши №5

Materials, equipment and reagents required for the experiment.

1. 
   Laboratory device.
   
2. 
   0.5N NaOH solution.
   
3. 
   0.5 liter Erlenmeyer flask.
   
4. 
   Methyl red indicator.
   
5. 
   Salt.
   
6. 
   Concentrated sulfuric acid.
   
7. 
   0.5N sulfuric acid.
   

Procedure:

In the laboratory, hydrogen chloride is obtained by the action of concentrated sulfuric acid on the salt. The reaction proceeds in two stages.
In the first stage, the reaction proceeds without external heat until a sour salt is formed:
NaCl + H2SO4 = NaHSO4 + HCl + Q
At the end of the first stage, when the process is exposed to external heat, the reaction proceeds as follows, and in the second stage a medium salt is formed:
NaCl + NaHSO4 = Na2SO4 + HCl - Q
The laboratory device for the production of hydrochloric acid is shown in the figure below. The flask (reactor) (1) is filled with a certain amount of extracted table salt and the calculated concentrated sulfuric acid is poured through the separating funnel (2).
A gas burner or electric hob (10) is connected to the bottom of the reactor (1). In the first stage, the hydrogen chloride formed without external heating may contain water and sulfuric acid vapors. The gas is concentrated from these vapors with concentrated sulfuric acid. Tishchenko is cleaned by passing it through the container (3). The droplet then passes through the holder (4) and enters the absorption column (5) through the barbell (6). Pre-distilled water is added to the absorption column, where the process of formation of hydrochloric acid - absorption takes place. The gas from the absorption column enters the vessel (8) (absorber) filled with sodium alkali, where the hydrogen chloride gas not absorbed in the absorption column is absorbed into the alkali.

Picture. Hydrochloric acid extraction laboratory device.

Note: The appliance must be located in the cupboard.

The temperature in the absorber is controlled by a thermometer (7). To create a gas flow, the device is connected to a water pump (9).

Add 50 ml of 0.5 N NaOH solution to the absorber (8). The hydrochloric acid formed at the end of the experiment is poured from the absorber (5) into the Erlenmeyer flask and titrated with 0.5 N NaOH, and the product formed in vessel (8) is titrated with 0.5 N H2SO4.
The degree of decomposition (with or without external heat) is determined by the following formula:



Here: Pi is the amount of alkali used to titrate the acid formed, ml.
Pk- (8) the amount of acid used to titrate the product formed in the absorber, ml.
fk, fi- Factors of acids and alkalis.
at- measuredsoupamount of salt.
The rate of absorption is determined using the following formula.