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ICSE Class 10 Chemistry Question 35 of 63

Study of Compounds — Nitric Acid — Question 35

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35
Question

Question 4(2011)

(i) State the special feature of the apparatus used in the laboratory preparation of nitric acid?

(ii) State why the temperature of the reaction mixture of HNO3 is not allowed to rise above 200°C.

Answer

(i) All glass apparatus is used since, the vapours of nitric acid being highly corrosive attack rubber, cork. etc.

(ii) Temperature above 200°C may cause:

  1. Damage to the glass apparatus.
  2. Further decomposition of nitric acid
  3. Formation of hard residual crust of the corresponding sulphate [Na2SO4 or K2SO4] which being a poor conductor of heat, sticks to the glass and cannot be easily removed from the apparatus.