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प्रश्न
Give reason why concentrated nitric acid prepared in the laboratory is yellow in colour. State how the colour of the acid is removed.
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उत्तर
The acid prepared in the laboratory decomposes slightly due to heat, releasing brown nitrogen dioxide (NO2) gas. This gas dissolves back into the acid, giving it a yellow colour.
\[\ce{4HNO3 ->[\Delta] 2H2O + 4NO2 + O2}\]
The yellow colour can be removed by bubbling dry air or carbon dioxide (CO2) gas through the acid to drive out the dissolved NO2, or by adding a little water, which converts the NO2 back into nitric acid.
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संबंधित प्रश्न
Fill in the blanks using the appropriate words given below :
(Sulphur dioxide, nitrogen dioxide, Nitric oxide, Sulphuric acid)
Hot, concentrated nitric acid reacts with sulphur to form ______________.
State one relevant observation for the following:
When crystals of copper nitrate are heated in a test tube.
What is the fixation of Nitrogen?
- Write a balanced chemical equation for the laboratory preparation of nitric acid.
- In the preparation of nitric acid from KNO3, concentrated hydrochloric acid is not used in place of concentrated sulphuric acid. Explain why?
- Conc. nitric acid prepared in the laboratory is yellow in colour. Why? How is this colour removed?
- Give reasons for the following:
In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitrate should not be heated very strongly above 200°C.
Give reasons for the following:
In the laboratory preparation of nitric acid, the mixture of concentrated sulphuric acid and sodium nitrate should not be heated very strongly above 200°C.
Identify the substance underlined:
The dilute acid which is an oxidizing agent.
Write the balanced equation for the following:
Action of concentrated nitric acid on copper.
Write down the word equation or balanced equation for the action of concentrated nitric acid on copper.
From the formulae listed below, Choose, one, corresponding to the salt having the given description:
AgCl, CuCO3, CuSO4.5H2O, KNO3, NaCl, NaHSO4, Pb(NO3)2, ZnCO3, ZnSO4, 7H2O.
On heating this, salt changes from green to black.
Convert the following reaction into a balanced chemical equation:
Ammonia to nitric oxide using oxygen and platinum catalyst.
