Detection Of Halogens
Halogens in an organic compound are not detected by directly adding silver nitrate to the compound but only after sodium fusion; what is the chief reason for this requirement?
Select the correct option:
🔒 Solution Hidden from View
Submit your answer to unlock the detailed step-by-step solution.
More purification and characterisation of organic compounds Practice Questions
The sodium fusion extract of an organic compound is acidified with dilute nitric acid and treated wi...
The sodium fusion extract of an organic compound is acidified with dilute nitric acid and treated wi...
In Carius method for estimation of halogens, an organic compound is heated with fuming HNO3 and AgNO...
In Carius method for estimation of halogens, an organic compound is heated with fuming HNO3 and AgNO...
When nitrogen in an organic compound is detected by Lassaigne's test, the appearance of a Prussian b...
When nitrogen in an organic compound is detected by Lassaigne's test, the appearance of a Prussian b...
In the combustion method, 0.20 g of an organic compound on complete combustion produced 0.366 g of c...
In the combustion method, 0.20 g of an organic compound on complete combustion produced 0.366 g of c...
In the Carius method for sulphur, 0.20 g of an organic compound yielded 0.466 g of barium sulphate; ...
In the Carius method for sulphur, 0.20 g of an organic compound yielded 0.466 g of barium sulphate; ...
Elemental analysis of an organic compound shows 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mas...
Elemental analysis of an organic compound shows 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mas...
In Carius method, 0.15 g of an organic compound containing chlorine gave 0.12 g of silver chloride; ...
In Carius method, 0.15 g of an organic compound containing chlorine gave 0.12 g of silver chloride; ...
In Kjeldahl's method, 0.30 g of an organic compound liberated ammonia that exactly neutralised 30 mL...
In Kjeldahl's method, 0.30 g of an organic compound liberated ammonia that exactly neutralised 30 mL...
An organic compound contains 40.0% carbon and 6.7% hydrogen with the remainder oxygen, and its molar...
An organic compound contains 40.0% carbon and 6.7% hydrogen with the remainder oxygen, and its molar...
Kjeldahl's method gives accurate nitrogen estimation for many compounds but fails for certain classe...
Kjeldahl's method gives accurate nitrogen estimation for many compounds but fails for certain classe...
In Duma's method, 0.42 g of an organic compound gave 60 mL of nitrogen gas collected over water at 3...
In Duma's method, 0.42 g of an organic compound gave 60 mL of nitrogen gas collected over water at 3...
A sodium fusion extract of an organic compound is treated with sodium nitroprusside and a violet col...
A sodium fusion extract of an organic compound is treated with sodium nitroprusside and a violet col...
Browse all purification and characterisation of organic compounds questions →
About This Question
- Subject
- chemistry
- Chapter
- purification and characterisation of organic compounds
- Topic
- detection of halogens
- Difficulty
- Medium
- Year
- 2025
Solution
Correct Answer:
Covalently bonded halogen must first be converted to free halide ions
In most organic compounds the halogen atom is bonded covalently to carbon and is therefore not available as a free halide ion in solution. Silver nitrate detects halogens by precipitating insoluble silver halides, but this requires the halogen to be present as ionic chloride, bromide, or iodide. Direct addition of silver nitrate to the organic compound fails because covalently bound halogen does not ionise and cannot form the precipitate. Sodium fusion solves this by reacting the compound with sodium metal, converting the covalent halogen into sodium halide (NaX), which is ionic and water soluble. The aqueous sodium fusion extract is then acidified with dilute nitric acid (to destroy cyanide or sulphide that would otherwise interfere) and treated with silver nitrate to give the characteristic precipitate. The claim about silver nitrate not dissolving in organic solvents misses the real point about covalent bonding. Raising temperature alone does not free the halide ion. Halogens do not simply evaporate away. This conversion of covalent halogen to ionic halide is the NCERT rationale. Plausibility check: only ionic halide can precipitate with silver ions, so fusion is essential.
This medium difficulty chemistry question is from the chapter purification and characterisation of organic compounds, covering the topic of detection of halogens. It appeared in the 2025 exam.
Looking for more practice? Explore all chemistry questions or browse purification and characterisation of organic compounds questions on RankGuru.