Question

Hard water gets softened on mixing with a solution of washing soda

Answer 1

Hard water can be softenedby adding washing soda (sodium carbonate) which removes the calcium ions in a precipitation reaction. Alternatively, the hard water can be passed through an ion-exchange resin in a column.

Hope this helps you

Answer 2

Applications of Electrolysis

Electrolysis has wide applications in industries. Some of the important applications are, as follows,  

(i) Production of hydrogen by electrolysis of water.

(ii) Manufacture of heavy water .

(iii) The metals like K, Mg, Al, etc., are obtained by electrolysis of fused electrolytes.

(iv) Non-metals like hydrogen, fluorine, chlorine are obtained by electrolysis.

(v) In this method pure metal is deposited at cathode from a solution containing the metal ions etc.

(vi) Compounds like NaOH, KOH, white lead, etc. are synthesised by electrosynthesis method.

(vii) Electroplating: The process of coating an inferior metal with a superior metal by electrolysis is known as electroplating