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प्रश्न
Explain the following:
Concentrated nitric acid appears yellow when it is left standing in a glass bottle.
Explain the following:
When it is left standing in a glass bottle, concentrated nitric acid appears yellow.
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उत्तर १
Although pure concentrated nitric acid is colourless, it appears yellow when left standing in a glass bottle due to the dissolution of reddish-brown nitrogen dioxide gas in the acid. The thermal decomposition of a portion of nitric acid produces nitrogen dioxide.
\[\ce{4HNO3 -> 2H2O + 4NO2 + O2}\]
उत्तर २
When exposed to sunshine, conc. nitric acid slowly decomposes into nitrogen dioxide gas, which is reddish brown. Nitrogen dioxide gas dissolves in nitric acid, causing it to turn yellow.
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संबंधित प्रश्न
Write a balanced equation and name the products formed when cupric oxide reacts with nitric acid.
Mention three important uses of nitric acid. Give the property of nitric acid involved in the use.
Explain with the help of a balanced equation the brown ring test for nitric acid.
How is nitric acid prepared in a laboratory?
- Name the process used for the manufacture of nitric acid.
- What are the reactants required for it and what are their sources?
- In which ratio reactants are taken in this process?
- Name the catalyst used in the process.
- What is the oxidizing agent in this process?
- Write the equations involved.
Complete and balance the following equation :
Fe + HNO3(conc.) → _____________
Fill in the blank with appropriate word/words.
3 Cu + 8 HNO3 (dilute) → _______ + 4H2O + _________
Name the compounds required for the laboratory preparation of 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.
Explain why only all-glass apparatus should be used for the preparation of nitric acid by heating concentrated sulphuric acid and potassium nitrate.
