Base solution question

[Tony L.]

I know you are not supposed to add water to acid, only acid to water. Can you add Basic solution (caustic Soda, 50%) to water or the other way around? Thanks.

[Chemnut]

I know you are not supposed to add water to acid, only acid to water. Can you add Basic solution (caustic Soda, 50%) to water or the other way around? Thanks.

 

The reason you add acid to water is for your safety. When adding one liquid to another, quite often a small amount splashes out. The substance that splashes out is the liquid in the container that the other solution is being added to. If you have a choice of what gets splashed out, I would chose water every time over acids and bases or other corrosives or hazardous chemicals. So, adding acid or base to water is the safest. Water will be the substance splashed out of the container.

 

Also, one should know a bit about the things they are adding together. Are they, or the reaction they cause, exothermic? Hydrating something like Sulphuric acid (or metals such as sodium, potassium, and other group one elements) generates a considerable amount of heat (reaction is very exothermic). Adding water to the acid too fast will result in the acid and water mixture leaving the container they were being mixed in.

 

Caustic Soda 50% and water is also exothermic but to a lesser extent than Sulphuric acid.

[Illiad]

Make it a habit to add anything (acid base) to water and not the other way around. You'll never know if someone's playing a practical joke (how unprofessional !) or if the assistant's having a bad day. If anything happens, a beaker of mostly water and a little acid/base is usually safer than a beaker of mostly acid/base and little water.