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प्रश्न
Why does pure nitric acid take on a yellowish brown colour when exposed to light?
उत्तर
Yellowish brown colour of nitric acid is due to the presence of nitrogen dioxide formed due to thermal decomposition of nitric acid.
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संबंधित प्रश्न
Name the gas evolved when the following mixtures are heated:
Sodium Nitrite and Ammonium Chloride
Ammonia is used in the Ostwald process.
Name the oxidising agent used in this process.
How will you prepare the following from nitric acid?
Aqua regia
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 action of heat on X.
- Write the equation between solution X and gas Z.
Nitric acid cannot be concentrated beyond 68% by the distillation of a dilute solution of HNO3, State the reason.
Give reason for the following:
Concentrated nitric acid is a stronger oxidizing agent.
Give two chemical tests for nitric acid.
Fill in the blank with appropriate word/words.
98% nitric acid is obtained by distilling 68% nitric acid with ________ under ______
Explain, why only all glass apparatus should be used for the preparation of nitric acid by heating concentrated sulphuric acid and potassium nitrate.
X, Y, and Z are three crystalline solids that are soluble in water and have 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.
