What happens when Gypsum is heated upto 373 ∘ K (Write only chemical equation).

Gypsum(calcium sulphate dihydrate) is heated to a temperature of 373 ° K 100 ° C to prepare Plaster of Paris in a kiln. During this chemical reaction, gypsum loses three-fourths of its water of crystallisation to form calcium sulphate hemi hydrate. Therefore, the following reaction is observed- CaSO 4 . 2 H 2 O Gypsum → ∆ , 100 ° C CaSO 4 . 1 2 H 2 O Plaster of Paris + 3 2 H 2 O Water

Write chemical formula of the following- Bleaching Powder

Bleaching powder is a white powder which has a strong smell of chlorine and that is why it is known as chloride of lime. It is soluble in cold water. The molecular name of bleaching powder is calcium oxychloride and the chemical formula is CaOCl 2 . It is mainly used as disinfecting agents, bleaching cotton, preparing chloroform, etc. This can be prepared by passing chlorine gas over dry slaked lime. Therefore, the following chemical reaction will take place- Ca OH 2 Calcium Hydroxide Slaked lime + Cl 2 Chlorine → CaOCl 2 Calcium oxychloride Bleaching Powder + H 2 O Water

Write chemical formula of the following- Plaster of Paris

Plaster of Paris is a white powder with a property of setting into hard mass on mixing with water. The chemical formula is CaSO 4 . 1 2 H 2 O or 2 CaSO 4 . H 2 O and molecular name is calcium sulphate hemi hydrate. It is used in making casts for statues, toys, fractured bones, etc. It is prepared by heating gypsum at 100 ° C and in which gypsum loses three-fourths of its water of crystallisation to form Plaster of Paris. CaSO 4 . 2 H 2 O Gypsum → ∆ , 100 ° C CaSO 4 . 1 2 H 2 O Plaster of Paris + 3 2 H 2 O Water

Write chemical formula and one use of the following- Baking Soda

Baking soda is a mild, non-corrosive base, consisting of white crystals which is sparingly soluble in water. The chemical name of baking soda is sodium hydrogencarbonate or sodium bicarbonate. Therefore, its chemical formula is NaHCO 3 . It is prepared on large scale by reacting a cold and concentrated solution of common salt with ammonia and carbon dioxide. NaCl + NH 3 + H 2 O + CO 2 → NaHCO 3 + NH 4 Cl The uses of baking soda are- It is used as an antacid to remove acidity of the stomach and fire extinguishers. It is widely used in making baking powder and soda water.

Write chemical formula and one use of the following- Washing Soda

Washing soda is a transparent crystalline solid with the molecular formula sodium carbonate decahydrate which contains ten molecules of water of crystallisation. The chemical formula of washing soda is Na 2 CO 3 . 10 H 2 O . It is prepared from soda ash. It has the cleansing properties for removing dirt and grease from dirty clothes. It is used in the manufacture of glass, soap, and paper.

What is the rain called when its pH value goes down from 5 . 6 ?

The pH scale was designed by Sorenson in 1909 which measures the strength of acid or base by making use of a hydrogen ion concentrations in them. The pH scale has values from 0 to 14 in which- Acids have a pH of less than 7 . Eg-Sulphuric acid. Bases have a pH of more than 7 . Eg- Caustic soda. Neutral substances have a pH of exactly 7 . Eg- Pure water. Therefore, the rain is called acid rain when its pH goes down from 5 . 6 because it has high concentration of hydrogen ions in it.

What happens when Gypsum is heated upto 373 ∘ K (Write only chemical equation).

Gypsum(calcium sulphate dihydrate) is heated to a temperature of 373 ° K 100 ° C to prepare Plaster of Paris in a kiln. During this chemical reaction, gypsum loses three-fourths of its water of crystallisation to form calcium sulphate hemi hydrate. Therefore, the following reaction is observed- CaSO 4 . 2 H 2 O Gypsum → ∆ , 100 ° C CaSO 4 . 1 2 H 2 O Plaster of Paris + 3 2 H 2 O Water