To prepare a soluble salt, we can react an acid with an insoluble base (hydroxide or oxide).
To prepare an insoluble salt, we can use precipitation method which is by mixing two solutions of soluble compound.

However, can I prepare an insoluble salt by reacting an acid with an insoluble base (hydroxide or oxide)?

For example,
1. Calcium hydroxide + Sulphuric acid
2. Lead (II) hydroxide + Sulphuric acid
3. Lead (II) hydroxide + Hydrochloric acid


1 Answer 1



The outside layer of the calcium hydroxide reacts with the sulfuric acid to form the calcium sulfate that you want. All good, until you realise that the newly-formed calcium sulfate is now coating the rest of the calcium hydroxide that didn't get to react. In the end you just get a big mess.

From a practical standpoint, even if your method worked, it's just much easier to just mix two solutions together and filter. No need to stir stuff and wait for insoluble powders to dissolve. On top of that, you're dissolving a white powder in order to make another white powder - how would you know when your reaction has finished?

Conclusion: Use calcium chloride and sodium sulfate.


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