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प्रश्न
Why is freshly prepared ferrous sulphate solution used for testing the nitrate radical in the brown ring test?
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उत्तर
We use freshly prepared ferrous sulphate solution because exposure to air, such as storing it in a reagent bottle, causes it to oxidise to ferric sulphate solution. The [NO] molecule will not form an additive compound with ferric sulphate; hence, the brown ring test will not be successful.
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संबंधित प्रश्न
Name the products formed when carbon and conc. nitric acid is heated.
Name the oxide of nitrogen which turns brown on exposure to air. How is it prepared?
Name the Following:
Salt referred to as chile saltpeter.
Can we use conc. HCl in place of Conc. H2SO4 ?
Give reason for the following:
Nitric acid is used in purification of gold.
Complete and balance the following equation :
FeSO4 + NO + H2O → ______________
Fill in the blank with appropriate word/words.
Aqua regia is a mixture of _______ and________
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.
Explain the following:
Concentrated nitric acid appears yellow when it is left standing in a glass bottle.
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.
