Preparation of sodium hydroxide standard solution

It’s best to first clarify the difference between preparation and configuration.

To prepare the sodium peroxide standard solution, 110 g of sodium peroxide is weighed and dissolved in 100 ml of water; the solution is then stored sealed until it becomes clear. But even after leaving the solution overnight, it remained cloudy. Guys, how long do you usually keep them? Can a standard solution be prepared if the solution is not clear?

When preparing a sodium hydroxide solution, since solid sodium hydroxide contains a small amount of sodium carbonate, if this small amount of carbonate does not affect its usability, there is no need to worry about it. If preparing a standard sodium hydroxide solution, it is necessary to dilute it using a concentrated sodium hydroxide solution. At this point, a sodium hydroxide solution of about 50% is required, that is, it is prepared by dissolving sodium hydroxide and water in a ratio of approximately 1:1. In the solution prepared in this way, sodium carbonate remains suspended in the solution in a slightly soluble state. Generally, by gently shaking the solution, these suspended slightly soluble substances will settle. If there is a large amount of suspended particles, it is likely that the sodium hydroxide has been stored for an extended period of time, resulting in a higher proportion of sodium carbonate. In such cases, it is best to use newly purchased sodium hydroxide for preparation, or to use more sodium hydroxide and quickly clean the surface of the solid sodium hydroxide with pure water before preparing the solution.

At around 20 degrees, I usually use a saturated sodium hydroxide solution to prepare standard solutions; their concentration is similar to that specified in national standards. Moreover, saturated solutions have good clarity, and the standard solutions prepared in this way also need to be calibrated before use, so there’s no need to worry about significant differences in concentration