Question

Instead of calcium hydroxide, why don't we simply add sodium hydroxide to seawater to precipitate magnesium hyroxide?

• A. Solubility of $Ca(OH{)}_2$ is higher than that of NaOH.
• B. NaOH may dissolve $Mg(OH{)}_2$ formed.
• C. NaOH may also precipitate other species.
• D. NaOH, being a weak electrolyte will not coagulte $Mg(OH{)}_2$

Answer 1

The correct option is C NaOH may also precipitate other species.

As NaOH is strong electrolyte than $Ca(OH{)}_2$ so it will provide more hydroxide ion and because of that it can also precipitate other species.