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प्रश्न
Give reason for the following:
Commercial concentrated nitric acid is yellow in colour, but when it is dilute with water, it turns colourless.
Give one chemical test for nitric acid.
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उत्तर
Commercial nitric acid is yellow in colour because of presence of nitrogen dioxide but when it is dilute with water, it turns colourless because nitrogen dioxide gets dissloved in water.
Brown ring test can be used to test nitric acid:
Brown ring test : Nitric acid in a test tube is taken and then 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.
\[\ce{6FeSO4 + 3H2SO4 + 2HNO3 -> 3Fe2(SO4)3 + 2NO + 4H2O}\]
\[\ce{FeSO4 + NO + 5H2O -> \underset{\text{Hydrated nitrosoferrous sulphate(brown ring)}}{[Fe(NO)(H2O)5]SO4}}\]
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संबंधित प्रश्न
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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:
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- The action of heat on Y.
- Concentrated nitric acid is added to copper turnings kept in a beaker.
Give a balanced equation for the following reaction:
Copper reacts with concentrated nitric acid.
