Chalk powder is a carbonate compound, insoluble in water.
Because of this property of chalk powder, it is easy to separate it from water.
The mixture containing chalk powder and water is allowed to get filtered.
(Filter paper can be used for filtration)
After filtration, the retentate obtained is chalk and the filtrate obtained is water without chalk.
The retentate is allowed to get dried and thence, chalk is obtained in powder form.
In this manner, we can separate chalk powder from water.