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Introduction of several methods to check whether barium hydroxide solid is deteriorated
- Categories:Industry news
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- Time of issue:2021-05-13 17:13
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Introduction of several methods to check whether barium hydroxide solid is deteriorated
- Categories:Industry news
- Author:
- Origin:
- Time of issue:2021-05-13 17:13
- Views:
1. Adding hydrochloric acid to the solid sodium hydroxide, if there are bubbles, it means the deterioration, because the solid sodium hydroxide will release a lot of heat when it dissolves, and it is a strong base, hydrochloric acid is a strong acid, and strong acid and strong alkali are also exothermic reactions. If the concentration of hydrochloric acid is above 1mol/L, it will directly react with the solid sodium hydroxide, and the hydrochloric acid will be boiled directly, so even if there is no deterioration, there will be a lot of water vapor and bubbles, which will interfere! It is best to first dissolve the sodium hydroxide, prepare a solution, and use a lower concentration of hydrochloric acid, or simply use a weak acid directly.
2. Prepare a solution, and then add clarified lime water or barium hydroxide solution to the solution. If there is precipitation, it proves that the sodium hydroxide has deteriorated! Because the solute of clarified lime water is calcium hydroxide, calcium hydroxide is originally slightly soluble, and its solubility decreases as the temperature rises. It happens that the sodium hydroxide dissolves and exotherms. You must wait until the sodium hydroxide solution is completely cooled to room temperature, but Waiting for it to cool down, the sodium hydroxide will react with carbon dioxide in the air. Therefore, unless the treatment is good or lucky, no matter how pure the sodium hydroxide solution is added to the lime water, it will precipitate; barium hydroxide This problem will not occur. If it is a laboratory, it is okay to see barium-containing substances in home laboratories, because except for barium sulfate, other barium salts are highly toxic.
3. Heating method, first put a stainless steel crucible with a lid into the desiccator for use, and use it when you need to check whether the solid sodium hydroxide has deteriorated!
Then put the solid to be measured into the crucible, cover the lid, fix it on the mud triangle, and then heat it with an alcohol lamp. If it is heated for 2 to 3 minutes, the solid will melt, indicating that it has not deteriorated; if it is heated for a long time, it is still If a part is not melted, it means it has deteriorated! Because the melting point of sodium hydroxide is more than 300°C, the melting point of sodium carbonate is more than 800. Because the crucible has been dried beforehand, it can rule out the possibility that the sodium hydroxide will deteriorate when heated! Because other tests have to wait for the solution to cool down, relatively speaking, this is faster.
4. Calculate by titration.
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