Q16 of 30 Page 1

List the important products of the Chlor-alkali process. Write one important use of each.

OR


How is washing soda prepared from sodium carbonate? Give its chemical equation, State the type of this salt, Name the type of hardness of water which tan be removed by it?


Important products of Chlor-alkali process are

(i) Sodium Hydroxide


Use: It is used for making soaps and detergents.


(ii) Chlorine


Use: It is used in the production of bleaching powder.


(iii) Hydrogen


Use: It is used in the production of Hydrochloric Acid,


OR


Washing soda is obtained by rehydration of anhydrous sodium carbonate.


Na2CO3 + 10H2O → Na2CO3.10H2O


It is the basic salt.


Na2CO3 can remove temporary and permanent hardness from water. Sodium carbonate is soluble but calcium carbonate and magnesium carbonate are insoluble.


The carbonate ions from sodium carbonate react with the calcium and magnesium ions in the water to produce insoluble precipitates. For example:


calcium ions + sodium carbonate → calcium carbonate + sodium ions


Ca2+(aq) + Na2CO3(aq) → CaCO3(s) + 2Na+(aq)


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14

Assertion (A) : In the process of nuclear fission, the amount of nuclear energy generated by the fission of an atom of uranium is so tremendous that it produces 10 million times the energy produced by the combustion of an atom of carbon from coal.

Reason (R) : The nucleus of a heavy atom such as uranium, when bombarded with low energy neutrons splits apart into lighter nuclei. The mass difference between the original nucleus and the product nuclei gets converted to tremendous energy.


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1 g of copper power was taken in a China dish and heated. What change takes place on basing? When hydrogen gas is passed over this heated substance, a visible change is seen in it. Give the chemical equations of reactions, the name and the color of the products formed in each case.

 17

3 mL of ethanol is taken in a test tube and warmed gently in a water bath. A 5% solution of alkaline potassium permanganate is added first drop by drop to this solution, then in excess.

(i) How is 5 % solution of KMnO4, prepared?


(ii) State the role of alkaline potassium permanganate in this reaction. What happens on adding it in excess?


(iii) Write chemical equation of this reaction.


 18

A squirrel is in a scary situation. Its body has to prepare for either fighting or running away. State the immediate changes that take place in its body so that the squirrel is able to either fight or run?

OR


Why is chemical communication better than electrical impulses as a means of communication between cells in a multi cellular organism?