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प्रश्न
How would you separate gold from a mixture of gold and copper filling?
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उत्तर
Gold will dissolve only in aqua regia i.e., a mixture of conc. hydrochloric acid and conc. nitric acid in 1:3 but copper will dissolve in nitric acid.
To separate gold from a mixture of gold and platinum add some nitric acid to the mixture, gold will remain undissolved hence can be filtered.
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संबंधित प्रश्न
What is the fixation of Nitrogen?
Conc. Nitric acid prepared in 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.
Write a balanced equation and name the products formed when sodium hydrogen carbonate is added to nitric acid.
Identify the substance underlined:
The dilute acid which is an oxidizing agent.
The following statement is correct only under certain conditions. Rewrite the statement including the appropriate condition(s) and underline it in your answer.
Copper and nitric acid react together to produce nitrogen dioxide.
Fill in the blank using the appropriate words given below:
Cold, dilute nitric acid reacts with copper to give ______.
Fill in the blank using the appropriate words given below:
Hot, concentrated nitric add reacts with sulphur to form ______.
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.
The diagram given below is a representation of the Industrial preparation of Nitric acid by Ostwald’s process. With respect to the process answer the following questions:
- Write the temperature and the catalyst required during the catalytic oxidation of ammonia.
- Give balanced chemical equation for the reaction occurring duringthe conversion of nitrogen dioxide to nitric acid.
