Often, when you make a solution involving an acid, do you grab some acid and pour water into it? Then this post is for you. Read till the end to find the right way to prepare a solution involving acids.
Let us look at two case scenarios of preparing an acidic solution-
- Adding water to acid
In this case, acids will release hydrogen ions (H+). When combined with water, they form hydronium ions (H3O+). This reaction is highly exothermic. The solution might start boiling to the point that it may splash and burn you.
Why is the reaction exothermic?
Acids, as you all know, donate hydrogen ions. When you add acid to water, the acids lose a hydrogen ion to water, forming hydronium ions. However, this also depends on the strength of the acid. Strong acids completely dissociate, while weak acids only partially dissociate.
Yet another reason is that, especially if you are diluting a solution of concentrated sulphuric acid, the dense acid will not mix well with water. It forms a layer of hot, weak acid solution that will boil and splash on you.
2. Adding acid to water
Just as in case 1, the reaction is the same. The acid will lose a proton to water to form hydronium ions. However, this reaction is relatively safer than the first. Here is why.
Adding small amounts of acid to water will also create an exothermic reaction, naturally. However, it will splash water droplets instead of acid. Keep note that this also has to be done slowly and carefully.
Adding small amounts of acid to a flask of water will allow the acid to flow down the water and mix better. This way, it neither boils nor splashes. The large amount of water can also absorb the heat of the reaction, making it a lot safer.
The mnemonic AAA- “Always Add Acid” will help you remember this trick.
Stay curious, Stay safe.
Informative!