"Laboratory Preparation Method of Chlorine Gas and Testing of Chloride Ions" Chlorine and Its Compounds PPT Courseware

Description

"Laboratory Preparation Method of Chlorine Gas and Testing of Chloride Ions" Chlorine and Its Compounds PPT Courseware

Part One: Literacy Goals

1. Review the carbon dioxide experimental device learned in junior high school, combine the properties of manganese dioxide and concentrated hydrochloric acid used to produce chlorine in the laboratory, select the appropriate experimental device to produce chlorine, cultivate a sense of scientific inquiry and innovation, and improve experimental ability.

2. Master the testing methods of chloride ions through comparative experiments, and cultivate evidence reasoning and scientific inquiry abilities.

Laboratory preparation of chlorine gas and testing of chloride ions PPT, part 2 content: independent preview before class

Knowledge foundation

1. When preparing gas in the laboratory, how to determine the gas generating device?

The prompts are based on the state of the reactants and reaction conditions (such as whether heating is required, etc.).

2. Gas collection method

Preview of new knowledge

1. Laboratory preparation method of chlorine gas

1. The reaction principle is MnO2+4HCl (concentrated) MnCl2+Cl2↑+2H2O.

2. Since the density of chlorine is greater than that of air, the upward air exhaust method can be used to collect chlorine.

3. Since chlorine is toxic, NaOH solution is used to absorb the exhaust gas. The reaction is Cl2+2NaOH=NaCl+NaClO+H2O.

2. Testing of chloride ions

Autonomous testing

1. Judge whether it is right or wrong (mark “√” if it is correct and “×” if it is wrong).

(1) After adding AgNO3 solution dropwise to the test solution, a white precipitate appears, indicating that the solution contains Cl-. ()

(2) When preparing Cl2 in the laboratory, MnO2 is used as the oxidant. ()

(3) Cl2 can also be produced when MnO2 reacts with dilute hydrochloric acid at high temperatures. ()

(4) When Cl2 is prepared in the laboratory, Cl2 often contains HCl impurities. ()

Answer(1)×　(2)√　(3)×　(4)√

2. A chemical interest group uses MnO2 and concentrated hydrochloric acid to prepare Cl2 using the device shown in the figure. Which of the following analysis is incorrect ()

In A.a, a separatory funnel can be used instead of a long-neck funnel.

B. lack of heating device in a

C.b contains NaOH solution to purify Cl2

If the catheter port in D.d is connected to an inverted funnel, it can prevent back suction.

AnswerC

The chlorine gas generated by analysis is easily mixed with hydrogen chloride gas. The hydrogen chloride should be removed with saturated salt water. Both hydrogen chloride and chlorine gas can react with sodium hydroxide solution, so sodium hydroxide solution cannot be held in b.

Laboratory preparation method of chlorine gas and testing of chloride ions PPT, part three content: classroom inquiry learning

Laboratory preparation method of Cl2

Question exploration

The following devices are typical devices for producing chlorine gas in the laboratory:

(1) What equipment does a complete set of equipment for laboratory gas production generally include?

The tips generally include: gas generating device → impurity removal device → collection device → exhaust gas treatment device.

(2) Chlorine is toxic. What safety measures should be taken when preparing chlorine in the laboratory?

Tip: You can conduct the experiment in a fume hood and use sodium hydroxide solution to absorb the exhaust gas.

(3) Manganese dioxide can only oxidize concentrated hydrochloric acid. When conducting this experiment, can the concentrated hydrochloric acid react completely?

Prompt cannot. As the reaction proceeds, concentrated hydrochloric acid turns into dilute hydrochloric acid, and the reaction stops.

(4) Combined with the raw materials and properties of chlorine produced in the laboratory, think about what impurities will be contained in chlorine and how to remove them.

It is suggested that hydrochloric acid is volatile, so Cl2 will contain HCl and water vapor. You can use saturated brine to remove HCl, and use concentrated sulfuric acid to absorb the water vapor.

Deepen and expand

1. Laboratory preparation method of chlorine gas

(1)Reaction principle

MnO2+4HCl(concentrated)==MnCl2+Cl2↑+2H2O

(2)Instruments and devices

Device features: solid + liquid → gas.

Main instruments: iron stand, alcohol lamp, round bottom flask, separatory funnel, gas collecting bottle, beaker, asbestos net, etc. The device is shown below.

Explanation: The function of device C is to remove HCl from Cl2; the function of device D is to dry Cl2; the function of device F is to absorb excess Cl2 to prevent environmental pollution.

(3)Collection method

① Upward air exhaust method (the density of Cl2 is greater than the density of air).

② Discharge saturated salt water method (the solubility of Cl2 in saturated NaCl solution is very small, and this method can remove the HCl gas generated by volatilization during the experiment).

(4) Fullness verification method

① Place the wet starch potassium iodide test paper close to the mouth of the bottle containing Cl2. If you observe that the test paper turns blue immediately, it proves that it is full.

② Place the moist blue litmus paper close to the mouth of the bottle containing Cl2. If you observe that the test paper immediately turns red and then fades, it proves that it is full.

(5) Exhaust gas treatment

Cl2 is toxic and easily pollutes the air, so it needs to be absorbed with NaOH solution.

2. Other methods of producing chlorine in the laboratory

KMnO4, KClO3, Ca(ClO)2 and other oxidants can be used instead of MnO2 to react with concentrated hydrochloric acid (no heating required), such as 2KMnO4+16HCl (concentrated) = 2KCl+2MnCl2+5Cl2↑+8H2O.

Laboratory preparation method of chlorine gas and testing of chloride ions PPT, part 4: on-site testing

1. The function of the reagent dilute nitric acid used when testing Cl- is ()

A. Prevent the interference of CO_3^2"-" B. Prevent the interference of Cl-

C. Generate Ag2CO3 precipitation D. Prevent the interference of NO_3^"-"

Answer A

When analyzing and testing Cl-, the added AgNO3 solution can react with CO to form a white precipitate of Ag2CO3, which interferes with the test of Cl-. Adding dilute nitric acid can eliminate the interference of C and the like.

2. Which of the following statements about the preparation of Cl2 from MnO2 in the laboratory is incorrect ()

A.MnO2 and concentrated hydrochloric acid are heated together

B. Slow heating reaction

C. Use the downward air exhaust method to collect Cl2

D. Excess chlorine is often absorbed with concentrated alkali solution

AnswerC

Analysis: Because concentrated hydrochloric acid is volatile, it must be heated slowly to reduce its volatilization; Cl2 is denser than air, so the upward air exhaust method should be used to collect Cl2; Cl2 can easily react with alkaline solutions, such as Cl2+2NaOH=NaCl+NaClO+ H2O, so a thicker alkali solution should be used to absorb excess Cl2.

3. It is known that the reaction between KMnO4 and concentrated hydrochloric acid at room temperature can produce Cl2. If you use the experimental device shown in the figure below to prepare pure, dry chlorine and verify its reaction with metal, each dotted box represents a unit device, and the one with errors is ()

A. ① and ② B. Only ②

C. ② and ③ D. ②③④

AnswerD

Analysis: ① is a device for generating chlorine gas, ② is a device for removing hydrogen chloride impurities in chlorine gas, ③ is a drying device, and ④ is a device for reacting chlorine gas with metal. The gas you want to retain cannot be consumed when removing impurities, because chlorine gas can react with NaOH solution, and the chemical equation is Cl2+2NaOH=NaCl+NaClO+H2O, so ② is wrong; ③The air inlet pipe is short, but the air outlet pipe is inserted under the liquid surface. The gas cannot be dried, nor can the gas enter ④ to react with the metal, so ③ is wrong; ④ is a closed system, and unreacted gas continues to accumulate, which will cause excessive pressure in the container and cause an explosion. The air inlet duct should be extended Enter the bottom of the test tube, so ④ is wrong.

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For more information about the PPT courseware "Laboratory Preparation of Chlorine Gas, Testing of Chloride Ions and Testing of Chlorine and Its Compounds", please click on the Laboratory Preparation Method of Chlorine ppt, Testing of Chloride Ions ppt, Chlorine and Its Compounds ppt tag.

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Update Time: 2024-10-02

This template belongs to Chemistry courseware People's Education Press High School Chemistry Compulsory Course I industry PPT template

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