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In Lassaigne’s test, nitrogen and sulphur both are present in an organic compound, sodium thiocyanate is formed.
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Important Questions on Organic Chemistry- Some Basic Principles and Techniques
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Phenol can be distinguished from ethanol by the reagent
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In the detection of nitrogen of an organic compound by Lassaigne's test, a prussian blue colour is obtained. This is due to the formation of which of the following complexes?
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The correct match between item and item is
| Item (Compound) | Item (Reagent) | ||
| Lysine | naphthol | ||
| Furfural | Ninhydrin | ||
| Benzyl alcohol | |||
| Styrene | Ceric ammonium nitrate | ||
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When nitrogen and chlorine containing organic compound is reacted with sodium metal, it forms
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Reagent, naphthylamine and sulphanilic acid in acetic acid is used for the detection of
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Which of the following compound will give blood red colour while doing the Lassaigne's test for .
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During the fusion of organic compound with sodium metal, nitrogen present in the organic compound is converted into
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Sodium extract is heated with concentrated before testing for halogens because :
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Match List-I with List-II
| List-I | List-II | ||
| Test/Reagents/Observation(s) | Species detected | ||
| (a) | Lassaigne's Test | (i) | Carbon |
| (b) | Cu(II) oxide | (ii) | Sulphur |
| (c) | Silver nitrate | (iii) | , and halogen |
| (d) | The sodium fusion extract gives black precipitate with acetic acid and lead acetate | (iv) | Halogen Specifically |
The correct match is :
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Which of the following compound is added to the sodium extract before addition of silver nitrate for testing of halogens?
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Match the organic compounds in column - with the Lassaigne's test result in column - appropriately:
| Column – | Column - | ||
| A. | Aniline | i. | Red colour with |
| B. | Benzene sulfonic acid | ii. | Violet color with sodium nitroprusside |
| C. | Thiourea | iii. | Blue color with and acidic solution of |
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Why is a solution of potassium hydroxide used to absorb carbon dioxide evolved during the estimation of carbon present in an organic compound?
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The Lassaigne's solution when heated with ferrous sulphate and acidified with sulphuric acid gives an intense blue colour indicating the presence of nitrogen. The blue colour is due to the formation of
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On adding to Lassaigne's extract of an organic compound, a black precipitate was obtained. What is the chemical composition of the black precipitate?
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When sodium nitroprusside is added to an alkaline solution of sulphide ions, it produces
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Discuss the chemistry of Lassaigne’s test.
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Will give white precipitate of on heating it with silver nitrate? Give reason for your answer.
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A compound heated with and then, boiled with and ammonium molybdate gives yellow precipitate. This shows the presence of
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Beilstein test is not used for fluorine because
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Write bond-line formulas for: .
