Question

plz someone solve this..

conc nitric acid prepared in laboratory is yellow in colour.. why? how is this colour removed ?

Answer 1

it clour was change when some acid is mix

Answer 2

When concentrated nitric acid is produced, a part of it decomposes as:
4HNO3--> 4NO2 + 2H2O + O2
This NO2 dissolves in the solution and produces a yellow colour.

To remove this, CO2 is bubbled in, which shifts the liquid-vapour equilibria of NO2, and removes it from solution, which gets oxidized and forms HNO3 again, thus the yellow colour is removed.