Advertisements
Advertisements
Question
Give two chemical tests for nitric acid.
Advertisements
Solution
Two tests for nitric acid are-
(i) Brown ring test :
Nitric acid in a test tube is taken and then freshly prepared ferrous sulphate solution is added. Concentrated H2SO4 is then added carefully down the sides of the test tube, dark brown ring is formed at the
junction of two layers.
\[\ce{6FeSO4 + 3H2SO4 + 2HNO3 -> 3FE2(SO4)3 + 2NO + 4H2O}\]
\[\ce{FeSO4 + NO + 5H2O -> \underset{\text{Hydrated nitrosoferrous Sulphate(brown ring)}}{[Fe(NO)(H2O)5]SO4}}\]
(ii) Nitric acid on heating gives brown fumes of nitrogen dioxide.
\[\ce{4HNO3 ->[\Delta] 2H2O + \underset{\text{Brown fumes}}{4NO2} + O2}\]
APPEARS IN
RELATED QUESTIONS
Write a balanced equation and name the products formed when zinc reacts with dilute nitric acid.
How will you prepare the following from nitric acid?
copper nitrate
Give the chemical name and formula of the substance formed as a brown ring in the test for nitrate radical.
Describe the Ostwald's process for the manufacture of nitric acid with labeled diagram.
Give reason for the following:
Commercial nitric acid is yellow in colour, but when it is diluted with water, it turns colourless.
Give reason for the following:
Conc. Nitric acid renders iron passive.
Write the equation for the laboratory preparation of nitric acid from potassium nitrate and concentrated sulphuric acid.
Account for the yellow colour that appears in concentrated nitric acid when it is left standing in an ordinary glass bottle.
Explain the following:
Dilute nitric acid is generally considered a typical acid but not so in its reaction with metals.
The figure given below illustrates the apparatus used in the laboratory preparation of nitric acid.
- Name A (a liquid), B (a solid), and C (a liquid). (Do not give the formulae.)
- Write an equation to show how nitric acid undergoes decomposition.
- Write the equation for the reaction in which copper is oxidised by concentrated nitric acid.
