What chemical reagents are used to distinguish the authenticity of purified water

Chlorine dioxide is chemically active, soluble in water, and has a solubility of 20, which is 5 times the solubility of chlorine. The oxidizing capacity is twice that of chlorine. Clo2 is a neutral molecule that exists almost 100% in a molecular state in water, and can only be converted into a soluble chloride by energizing it to produce an electrolytic effect and reacting with free metals in water with the chemical formula clo2+2h2o+4e cl+4oh

The use of chlorine dioxide disinfection can also oxidize some reducing metal ions in water (such as Fe2+, Mn2+, etc.), that is, it has a good effect on iron and manganese in water. Chlorine dioxide disinfection generally only acts as an oxidation and does not have a chlorinating effect. And after disinfection with chlorine dioxide, its content in purified water is very low, and it is difficult to detect with ordinary reagents.

The disinfection of tap water is generally disinfected by lime or chlorine, tap water often has the smell of chlorine, and chlorine will ionize chlorate ions and hypochlorite ions in the water, these substances can make the water acidic, so I think it can be identified by litmus solution.

c. Silver nitrate is broadcast in Guangdong news, that is, it is about filling bottled water with tap water.

Silver nitrate is used in analytical chemistry for the determination of chlorine, bromine, iodicyanide and thiocyanate, and as a catalyst for the determination of manganese.

Please examine the question carefully: tap water is often used for chlorine dioxide sterilization and disinfection, which can be converted into soluble chloride, so the question is the test of chloride ions, and silver ions and chloride ions form white silver chloride precipitates. Therefore, C is chosen.

c。。The chloride ions of silver ions and chlorides form a white precipitate.

How to distinguish between purified water and mineral water:

1. Take two liquids in the same envy state and put them in the test tube, and add the same volume of soapy water.

2. Pure water with more foam, and mineral water with less foam and scum is produced.

3. Because mineral water is natural water, it contains a large amount of soluble calcium and magnesium compounds, which can react with unsaturated fats and sodium in soapy water to form insoluble substances, so that the soap does not bubble, and slips and produces scum.

1. Take the two liquids in the first volume of the equal body manuscript stove and put them in the test tube, and add the same volume of soapy water,**;

2. The bubble and foam are pure water, and the mineral water produced by less foam and scum is produced;

3. Mineral water is a natural water, which contains a large amount of soluble calcium and magnesium compounds, which can react with unsaturated fats and sodium in soapy water to form insoluble substances, so that the soap does not bubble and produces scum, while pure water will not appear scum.

1. Take two liquids of the same volume and put them in the test tube, and add the soapy water of the same volume of the sail, **;

2. The foam is pure water, and the mineral water produced by the foam and scum;

3. Mineral water is natural water, which contains soluble calcium and magnesium compounds with large landslide hail, which can react with unsaturated fat and sodium in soapy water to form insoluble jujube grips, so that the soap does not bubble and produces scum, while pure water will not appear scum.

b.Sodium hydroxide test solution.

1. In the dissolution process, it will be found that there is some turbidity around the solid, but once it is dissolved, after stirring evenly, the solution will be clear, which is due to the NaOH fixed in the preparation process, which contains a lot of tiny bubbles, in the dissolution process, the tiny bubbles are released, plus the dissolution itself is exothermic, the water is originally dissolved with part of the air, and when the local temperature rises, these dissolved gases are also released to form tiny bubbles;

2. For solids that dissolve quickly, especially those that will expand when exposed to water, due to the rapid absorption of water, the solids will be decomposed into small particles, which have not had time to dissolve when they diffuse into water, and it looks like the liquid has become turbid, but it will soon be clear.

3. If it is dissolved, it is still turbid after full stirring, and the water used may not be pure water, and ordinary tap water contains some minerals, such as Mg2+, Ca2+, etc., which will produce white precipitation in the alkaline solution, causing the liquid to be turbid, but as long as it is fully standing, it will also restore clarity.

Methods: Samples were taken dropwise with dilute nitric acid acidified silver nitrate solution, and tap water was produced by white precipitate, and mineral water was mineral water without obvious phenomenon.

Analysis: The tap water is disinfected with chlorine, which has residual chloride ions, which reacts with silver nitrate to form silver chloride white precipitate.

Cl-+AG+==AGCL (white precipitate).

Mineral water contains only trace amounts of minerals, and the addition of silver nitrate does not react.

Hope it helps.