The pH values of the calcium chloride and sodium tetraborate solutions actually turned acidic
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This post was last edited by Shuizhu@Chenfu on 2021-9-28 09:33. When preparing calcium chloride coolant, I used sodium tetraborate as a corrosion inhibitor; however, an unexpected situation occurred. I would like to ask everyone for advice: 1. When 43 g of anhydrous calcium chloride is added to 100 g of water and dissolved, the pH value is 8.2. Upon gradually adding 1 g of sodium tetraborate, the pH value decreases, eventually reaching 5.2. 2. In another container, add 100 g of water and 1 g of sodium tetraborate; after dissolution, the pH value is 9.2. Then add 43 g of anhydrous calcium chloride, and the pH value eventually drops to above 5.3. In all cases, the same anhydrous calcium chloride and sodium tetraborate as well as pure water were used. The pH meter was calibrated using standard solutions of 4.0 and 6.82. This approach is highly unreasonable – two alkaline substances combined end up forming an acidic substance, moreover with a high degree of acidity.
This isn’t scientific – both are alkaline substances, yet when combined they turn into an acidic substance! ! ! !
Consider this: CaCl2 should be neutral or slightly acidic; it should not be alkaline； The ingredients are not pure, or CO2 in the air affects the solution being prepared.