1. Write down the preparation, 2 properties and 2 uses for the following :-
(a) Washing soda.
(b) Baking soda.
(c) Bleaching powder.
(d) Plaster of paris.
2. Why does a transformer not work in DC?

Washing soda:

Washing soda is also produced from common salt. The chemical name of washing soda is hydrated sodium carbonate and its chemical formula is Na₂CO₃.10H₂O. It is obtained by heating sodium hydrogen carbonate.

The re-crystallization of sodium carbonate produces washing soda.

Sodium carbonate is used in the manufacturing of glass, soap, and paper. It is also used for the manufacturing of borax, for removing permanent hardness of water.

Baking soda:

We know that baking soda is most commonly used in the kitchen for making delicious pakoras. The chemical name of baking soda is sodium hydrogen carbonate (NaHCO₃). Baking soda is produced by using sodium chloride as one of the raw materials. The chemical equation can be represented as follows:

Sodium hydrogen carbonate is used as an ingredient in antacids. It is alkaline in nature. Hence, it neutralizes excess acid in the stomach and provides relief.

Sodium hydrogen carbonate is also used in soda acid fire extinguishers. It is also used for cooking and sometimes, it is added for faster cooking. The following reaction takes place when it is heated during cooking:

Bleaching powder:

Chlorine gas obtained in the electrolysis is used for the manufacture of bleaching powder. Chlorine gas on reacting with dry slaked lime [Ca(OH)₂] produces bleaching powder (CaOCl₂). The chemical equation involved in the reaction can be represented as:

Bleaching powder is used for disinfecting water to make it germ-free. It is used in the textile industry to produce cotton and linen materials. It is also used as an oxidizing agent in many chemical industries.

Hemihydrated form of calcium sulphate is known as Plaster of Paris. It is in the form of a white powder.

When the powder of Plaster of Paris is mixed with water, it becomes hard and solid gypsum. Plaster of Paris is generally used to support fractured bones in their correct positions.

In, only half a water molecule is shown as the water of crystallization because two molecules of CaSO₄ share one molecule of water.

Plaster of Paris is used for making toys, materials for decoration, and for making smooth surfaces.