Why can t potassium permanganate replace potassium dichromate in a configuration lotion? Thank you f

Potassium permanganate and potassium dichromate are both oxidizing agents, but they differ in oxidizing properties.

Potassium permanganate (KMNO4) is a strong oxidizing agent, and its oxidation is mainly derived from the element manganese (MN). Potassium permanganate can release manganese dioxide (mnO2) and oxygen under acidic conditions, while it is less oxidative under neutral or alkaline conditions. Therefore, potassium permanganate can be used to oxidize organic matter under acidic conditions, but its oxidation is limited under neutral or alkaline conditions.

Potassium dichromate (K2Cr2O7) is also an oxidizing agent, but it is more oxidizing than potassium permanganate. Under acidic conditions, potassium dichromate can release chromium trioxide (CRO3), which is more oxidizing than potassium permanganate. Therefore, potassium dichromate can be used to oxidize stronger organics under acidic conditions.

Therefore, if stronger organics need to be oxidized, potassium dichromate is a better choice. If weaker organics need to be oxidized, potassium permanganate is a better choice. Therefore, potassium permanganate cannot simply be used instead of potassium dichromate to prepare the lotion.

Potassium permanganate has strong oxidation, and the electrode potential can be compared: E (potassium permanganate manganese ion) =, E (potassium dichromate chromium ion) =, the electrode potential is an important criterion for comparing the amount of oxidation. Potassium dichromate is toxic, carcinogenic, and is used less often.

However, potassium dichromate is more stable than potassium permanganate and easy to preserve.

Potassium permanganate is too unstable and has poor preservation. Potassium dichromate can be made into a lotion and stored for a period of time.

There are two formulations for potassium dichromate lotion.

1. Formula 1; : Strong lotion.

Potassium dichromate 150g, distilled water 300ml, concentrated sulfuric acid 3 000ml2, formula 2: This is a medium-strength lotion.

Concentrated sulfuric acid 50%, distilled water 50%, potassium dichromate 5% 3Operation: Add potassium dichromate to distilled water to dissolve it naturally or in a water bath, then slowly add concentrated sulfuric acid, stir while adding, stop for a moment when the fever is too severe, and continue to add after cooling.

Wear rubber aprons, long rubber boots, glasses and thick rubber gloves to ensure safety.

There are a few requirements for substances that can be directly formulated as standard solutions:

1.The composition is exactly the same as the molecular formula.

2.The purity is high enough.

3.The relative molecular mass is large.

4.The chemical reactions involved can be carried out quantitatively and quickly.

K2Cr2O7 meets the above conditions and can be directly prepared as a standard dissolved pure tan solution. The main problem with KMNO4 is that the purity of Tonia is not enough, and more or less of it will be mixed with Mn(VI) and Mn(IV), so it cannot be directly prepared as a standard solution. In the laboratory, after preparing KMNO4 solution, it should be placed in a dark place for a period of time, and then the insoluble mnO2 should be filtered out, and then its concentration should be accurately calibrated with other reference substances.

Is it a lotion of glassware used in hospitals?

To prepare a 5% solution in the hospital, a ratio of 5 grams of potassium dichromate to 100 ml of distilled water is required. A small amount of sulfuric acid can be added dropwise to the prepared solution.

20g of K2Cr2O7, dissolved in 40ml of water, 360ml of concentrated H2SO4 is slowly added to K2Cr2O7 solution (water or solution must not be added to H2SO4), stir with a glass rod while pouring, and be careful not to splash, mix evenly, after cooling, put it into a lotion bottle for standby The newly prepared lotion is reddish-brown, and the oxidation ability is very strong, when the lotion becomes black-green after a long time (solid potassium permanganate can be added to regenerate it), that is, the lotion has no oxidation washing power.

Potassium dichromate standard solution.

1.Make up. Weigh 5g potassium dichromate, dissolve in 1000ml of water, and shake well.

2.Demarcate. Measure (prepared potassium dichromate solution, put it in a 250ml iodine measuring flask, add potassium iodide, gently shake to dissolve, add 20ml of 20% sulfuric acid, shake well, and plug; After 10 minutes in the dark, dilute with 150ml of water, titrate with sodium thiosulfate standard solution, and add 3ml of starch indicator solution (5g L) near the endpoint, continue to titrate until the blue disappears and the green color is bright, and the blank experiment is performed at the same time.

3.Calculation: The dosage of potassium dichromate solution in V——— mL is in the formula;

C1 (Na2S2O3) - the amount and concentration of sodium thiosulfate standard solution, mol l;

V1——— the amount of sodium thiosulfate standard solution at the time of titration ml;

V2——— the amount of sodium thiosulfate standard solution during blank titration ml;

The most common preparation method: potassium dichromate (g): water (ml): concentrated sulfuric acid (ml) = 1:2:18

1. Add potassium dichromate powder to hot water, heat and dissolve. This process is very painful, potassium dichromate is not very soluble, you can grind it, and the dissolution speed will be much faster.

2. After basically dissolving to the bottom without particles, carefully add concentrated sulfuric acid, note, you must be careful, pour it quickly and it is easy to splash out the solution, when you add 40ml of sulfuric acid (20g potassium dichromate solution), the lotion will have solute precipitation, don't worry, this means that you can rest assured that you can boldly pour the remaining concentrated sulfuric acid into, the solution will be restored to clarity, and the lotion will be naturally prepared!

3. All you have to do is wait for it to cool down, and of course, please don't leave it open.

4. Preservation: There is concentrated sulfuric acid, which is easy to absorb moisture, and it is easy to deteriorate when it absorbs moisture, so it is best to put it in a dry environment. Never put it next to the sink.

Potassium dichromateNeed to use it on the spot.

Use potassium dichromate, and add koh to adjust to weak alkalinity after mixing.

The dosage of K2Cr2O7 + 2KOH = 2K2CRO4 + H2O potassium dichromate can be converted according to: K2Cr2O7 2K2CRO4 relationship.

Potassium dichromateIt is an inorganic compound of spring shed ant.

The chemical formula is K2Cr2O7 and orange-red at room temperature.

Crystalline powder, soluble in water, insoluble in ethanol.

Potassium dichromate is a strong oxidant that is toxic and carcinogenic.

It is classified as a Class I carcinogen by the Guohe Cellulite Research Institute, and it is a strong oxidizing agent, which has a wide range of applications in the laboratory and industry. It is used to make chrome alum, matches, chrome pigments, and for tanning, electroplating, organic synthesis, etc.

The above content reference: Encyclopedia - Potassium dichromate.

When inhaling large amounts of chromic acid or chromate, quickly transfer to fresh air to keep the airway open and oxygen. 2. **In contact with chromic acid or chromate, the wound should be cleaned with water immediately. 3. Oral poisoning, gastric lavage, 50 mg sulfate 60ml catharsis, milk and egg white to protect the gastric mucosa.

Storage & Transportation Store in a cool, dry place, and the container must be sealed to prevent moisture. It is stored and transported in isolation from organic matter, flammable matter, reducing agent, easy oxide and acid.

Safety & Handling 1. Extract air from the electroplating tank in the electroplating workshop to discharge chromic acid mist, and acid mist preparations can be used in the tank. 2. The workshop is equipped with a special faucet in order to rinse the eyes and eyes in time. 3. Strengthen personal protection. 4. Health monitoring, pre-employment physical examination.

Potassium dichromateOpen Categories: Chemistry, Chemical Reagents.

Chinese name: potassium dichromate; Potassium alum.

Product Name: potassium bichromate; potassium dichromate

Structure or Molecular Formula K2Cr2O7 Relative Molecular Weight or Atomic Weight Density Relative Density Solubility 20 Solubility in water is 12 grams. Melting point ( )398 Character: Orange-red triclinic crystal or needle-like crystal. Solubility Soluble in water, insoluble in ethanol.

Usage: For the production of chrome alum. matches, chrome pigments, and for tanning, electroplating, organic synthesis, etc. Prepared or** can be prepared by metathesis of sodium dichromate with potassium chloride or potassium sulfate.

Others release oxygen at white-hot temperatures and have strong oxidizing properties.

There are a few requirements for substances that can be directly formulated as standard solutions:

The composition is exactly the same as the molecular formula.

The purity is high enough.

The relative molecular mass is large.

The chemical reactions involved can be carried out quantitatively and quickly.

K2Cr2O7 meets the above conditions and can be directly prepared as a standard solution. The main problem with KMNO4 is that it is not pure enough, and some of it will be mixed with Mn(vi) and Mn(IV), so it cannot be directly prepared as a standard solution. In the laboratory, after preparing KMNO4 solution, it should be placed in the dark for a period of time, and then the insoluble mnO2 should be filtered out, and its concentration should be accurately calibrated with other reference materials.