Name the following. A colloidal solution

A colloidal solution is a heterogeneous mixture in which solute particles are neither dissolved nor settled down, and cannot be filtered by filter paper. Example - Milk and Starch in water.

Name the following. Chemicals that can cause temporary hardness of water

Dissolved calcium and magnesium bicarbonates cause temporary hardness of water. Due to the presence of these soluble salts what does not lather with soap easily.

Name the following. A method to remove the temporary hardness of water.

A method to remove temporary hardness of water is boiling the hard water. This settles down the insoluble bicarbonates which could be further filtered out.

Name the following. A hydrated salt.

Hydrated salts are compounds having fixed water molecules loosely bound per molecule of the salt. Some of these salts acquire a colour due to the presence of water of crystallisation. For example, CuSO 4 . 5 H 2 O is a blue-coloured hydrated salt. When these water molecules are removed from the salt on heating, the salt turns white.

Write a balanced chemical reaction between the following: Sodium metal with water.

When sodium reacts with cold water it produces sodium hydroxide with the liberation of hydrogen gas. It is an exothermic reaction. 2 Na ( s ) + 2 H 2 O ( l ) → 2 NaOH ( l ) + H 2 ( g )