Common characteristics between sodium carbonate and sodium bicarbonate vs. sodium carbonate and sodium bicarbonate
1. It can react with hydrochloric acid (or sulfuric acid and nitric acid) to generate gas that can make clear lime water turbid;
2. White precipitate will be generated with lime water or barium hydroxide solution;
3. Aqueous solutions are alkaline;
4. The flame reaction is yellow;
5. It can undergo double hydrolysis reaction with aluminum salt or iron salt solution;
The difference between sodium carbonate and sodium bicarbonate vs. sodium carbonate and sodium bicarbonate
1. Thermal stability: sodium carbonate does not decompose when heated, while sodium bicarbonate easily decomposes into sodium carbonate, water and carbon dioxide when heated;
2. Water solubility: Solubility of sodium carbonate is greater than sodium bicarbonate;
3. Reaction with carbon dioxide: Sodium carbonate can combine with carbon dioxide (and water) to form sodium bicarbonate, but sodium bicarbonate does not react;
4. Reaction with sodium hydroxide: sodium bicarbonate can react with sodium hydroxide to form sodium carbonate and water, but sodium bicarbonate does not react;
5. Reaction with calcium chloride: Sodium carbonate and calcium chloride (or barium chloride) solutions easily form carbonate precipitation, while sodium bicarbonate and salt dilute solutions do not easily form precipitation
6. Reaction with phenol: Sodium carbonate can react with phenol to form sodium phenolate and sodium bicarbonate, but sodium bicarbonate does not react with phenol;
How to distinguish sodium carbonate and sodium bicarbonate vs. sodium carbonate and sodium bicarbonate
1. Solid state
Method 1: Depending on the thermal stability. A small amount of the sample is heated separately and the resulting gas is passed through clarified limewater. The sample that can make clear limewater turbid is sodium bicarbonate. The instrument used in this method is relatively complex and requires a heating device.
Method 2: Depending on the rate of reaction with acid. Take solids of the same mass and add them to hydrochloric acid of equal concentration and volume. The one that reacts faster is sodium bicarbonate. This method is somewhat difficult to observe.
2. Solution state
Method 3: Depending on the reaction process with acid. Take solutions of the same concentration and volume, and add hydrochloric acid dropwise. The solution that becomes gasless after a period of time is sodium carbonate; the solution that becomes gasy at the beginning is sodium bicarbonate. When the concentration of the solution is relatively low, the bubbles will not be obvious;
Method 4: It depends on the precipitation reaction. Take the dilute solutions respectively and add BaCl2 (or CaCl2) solution and heavy magnesium carbonate dropwise. The original reagent that produces precipitation is sodium carbonate.
Method 5: Depending on the alkalinity of the solution. Measure the pH of dilute solutions of equal concentration. The original reagent with a larger pH value is sodium carbonate. It is necessary to prepare solutions with equal amounts and concentrations of substances;
Method 6: Based on the amphoteric properties of sodium bicarbonate. Take the solutions separately and add sodium metaaluminate solution dropwise to the neodymium carbonate dihydrate. The white precipitate generated is sodium bicarbonate.
3. Wrong method
Method 1: Use clarified lime water. Because both sodium bicarbonate solution and sodium carbonate solution can react with clear lime water to form a white precipitate, clear lime water cannot identify the two solutions.
Method 2: Use ferric chloride. Because both sodium bicarbonate solution and sodium carbonate solution can react with ferric chloride to form precipitate and gas, ferric chloride solution cannot identify the two solutions.
Method 3: Use sodium hydroxide. Although the sodium bicarbonate solution can react with sodium hydroxide, the phenomenon is not observed, so the sodium hydroxide solution cannot differentiate between the two solutions.
4. Removing sodium bicarbonate from sodium carbonate
1. Remove sodium bicarbonate impurities from sodium carbonate solid and heat in air;
2. Remove sodium bicarbonate impurities in the sodium carbonate solution and add an appropriate amount of sodium hydroxide;
5. Removing sodium carbonate from sodium bicarbonate
