Chapter no. 2
            Acids, Bases And Salts
Very Short Answer Type Questions
Q.1. What is aqua regia ?
Ans.The fresh mixture of conc. H2SO4 and conc. HNO3 in the ratio 3:1 is called Aqua regia.

Q.2. What is Gypsum ? What happens if it is heated upto 100•C.
Ans. Gypsum is a substance found in capital of france ( paris) when it is heated at 100C then the plaster of peris is formed.

Q.3. What is washing soda ? Write its two properties and two uses.
Ans.Washing soda is white crystalline solid with 10 molecules of water. Its chemical formula is Na2CO3.10H2O
Properties: (i) It is a white crystalline solid.
(ii) It is soluble in water.
Uses: (i) It is used as detergent.
(ii) It is used in manufacture of glass, caustic soda, soap etc.

Q.4. Write two important uses of plaster of paris.
Ans. (i) It is used as plaster for supporting fractured bones in right position.
(ii) It is used to make frame of denture.

Q.5. How is slaked lime is obtained by lime stine ( quick lime ).
Ans. The slaked lime is obtained by the reaction of lime stone with water. In the reaction heat is produced.


              CaO+H2O➡Ca(OH)2+Heat


Short Answer Type Questions
Q.1.Why does an aqueous solution of an acid conduct electricity ? 
Ans. For the conduction of electricity through solutions, tghe ions are required. We know that the aqueous solution of acids gives H+ ions which are responsible for conduction of electricity.

Q.2. While diluting an acid, why is it recommended that the acid should be added to water and not water to acid ?
Ans. The dilution process of an acid in water is highly exothermic. A large amount of heat is evolved in this process. So in the dilution process precautions should be taken. The acid should be added to water very slowly and with continuous shaking. On the other hand if water is added to acid due to sudden release of heat it might spill on your body and clothes.
Q.3. Why does distilled water not conduct electricity whereas rain water does ?
Ans.Distilled water contains no ions, so it can not conduct electricity whereas rain water contains ions of acids so it comducts electricity, in rainwater carbon dioxide is dissolved so carbonic acid formed The acid on decomposition gives ions which help in the conduction of electricity .
(i) CO2+H2O➡H2CO3



Q.4. Give two important uses of washing soda and baking soda .
Ans.  Used of baking soda: (i) It is used as antacid.
(ii) It is used as fire extinguisher.
uses of washing soda : (i) It is used in manufacturing of glass soap and in paper industry .
(ii) It is used manufacture of sodium compound like borex etc.