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प्रश्न
Give two chemical tests for nitric acid.
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उत्तर
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.
\[\ce{4HNO3 ->[\Delta] 2H2O + \underset{\text{Brown fumes}}{4NO2} + O2}\]
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संबंधित प्रश्न
What is the type of salt formed when the reactants are heated at a suitable temperature for the preparation of nitric acid?
Name the products formed when dilute HNO3 is added to copper.
Name a metal nitrate which on heating is changed into metal.
The action of heat on the blue crystalline solid X gives a reddish brown gas Y, a gas which re-lights a glowing splint and leaves a black residue. When gas Z, which has a rotten egg smell, is passed through a solution of X, a black ppt. is formed.
- Identify X, Y and Z.
- Write the equation for the action of heat on X.
- Write the equation between solution X and gas Z.
Name the catalyst used in Ostwald process.
Complete and balance the following equation :
FeSO4 + NO + H2O → ______________
Fill in the blank with appropriate word/words.
98% nitric acid is obtained by distilling 68% nitric acid with ________ under ______
The figure given below illustrates the apparatus used in the laboratory preparation of nitric acid:
(i) Name A (a liquid), B( a Solid) and C(a liquid).
(ii) write the balanced chemical equation to show how nitric acid undergoes decomposition.
(iii) Write the balanced chemical equation for the reaction in which copper is oxidized by concentrated nitric acid.
X, Y and Z are three crystalline solids that are soluble in water and have a common anion.
To help you to identify X, Y and Z, you are provided with the following experimental observations. Copy and complete the corresponding inferences in (a) to (e).
- A reddish-brown gas is obtained when X, Y and Z are separately warmed with concentrated sulphuric acid and copper turning added to the mixture.
INFERENCE 1: The common anion is the ______ ion. - When X is heated, it melts and gives off only one gas which re-lights a glowing splint.
INFERENCE 2: The cation in X is either ______ or ______. - The action of heat on Y produces a reddish-brown gas and yellow residue which fuses with a glass of the test tube.
INFERENCE 3: The metal ion present in Y is the ______ ion. - When Z is heated, it leaves no residue. Warming Z with sodium hydroxide solution liberates a gas which turns moist red litmus paper blue.
INFERENCE 4: Z contains the ______ cation. - Write the equations for the following reactions:
- X and concentrated sulphuric acid (below 200°C). (One equation only for either of the cations given in INFERENCE 2)
- The action of heat on Y.
- Concentrated nitric acid is added to copper turnings kept in a beaker.
From the following list of substances, choose one substance in the case which matches the description given below:
Ammonium nitrate, calcium hydrogen carbonate, copper carbonate, lead nitrate, potassium nitrate, sodium carbonate, sodium hydrogen carbonate, zinc carbonate.
A Substance that gives off only oxygen when heated.
