To determine which nitrogen-containing compound does not respond positively to the Lassaigne test for nitrogen, we need to understand the principle of the Lassaigne test and the expected results for different compounds.

The Lassaigne test is a chemical test used to detect the presence of nitrogen in organic compounds. In this test, the organic compound is heated with sodium metal, which converts the nitrogen present in the compound into sodium cyanide (NaCN). The resulting sodium cyanide is then treated with ferrous sulfate (FeSO4) and sulfuric acid (H2SO4) to form a deep blue precipitate of Prussian blue.

Now, let's consider the nitrogen-containing compounds and their expected results in the Lassaigne test:

1. Amines: Amines are organic compounds that contain a nitrogen atom bonded to one or more alkyl or aryl groups. Amines typically respond positively to the Lassaigne test, producing a blue precipitate of Prussian blue.

2. Amides: Amides are organic compounds that contain a carbonyl group (C=O) bonded to a nitrogen atom. Amides also respond positively to the Lassaigne test, forming a blue precipitate of Prussian blue.

3. Nitriles: Nitriles are organic compounds that contain a carbon triple bond to a nitrogen atom (C≡N). Nitriles do not respond positively to the Lassaigne test for nitrogen. Instead, they produce a yellow precipitate of sodium sulfocyanide (NaSCN) due to the reaction between sodium cyanide and sulfur present in the test reagents.

4. Nitro compounds: Nitro compounds contain a nitro group (-NO2) bonded to a carbon atom. Nitro compounds do not respond positively to the Lassaigne test for nitrogen. Instead, they produce a yellow precipitate of sodium sulfocyanide (NaSCN) similar to nitriles.

Based on the information above, the nitrogen-containing compound that does not respond positively to the Lassaigne test for nitrogen is nitriles.

Question

To determine which nitrogen-containing compound does not respond positively to the Lassaigne test for nitrogen, we need to understand the principle of the Lassaigne test and the expected results for different compounds.

The Lassaigne test is a chemical test used to detect the presence of nitrogen in organic compounds. In this test, the organic compound is heated with sodium metal, which converts the nitrogen present in the compound into sodium cyanide (NaCN). The resulting sodium cyanide is then treated with ferrous sulfate (FeSO4) and sulfuric acid (H2SO4) to form a deep blue precipitate of Prussian blue.

Now, let's consider the nitrogen-containing compounds and their expected results in the Lassaigne test:

1. Amines: Amines are organic compounds that contain a nitrogen atom bonded to one or more alkyl or aryl groups. Amines typically respond positively to the Lassaigne test, producing a blue precipitate of Prussian blue.

2. Amides: Amides are organic compounds that contain a carbonyl group (C=O) bonded to a nitrogen atom. Amides also respond positively to the Lassaigne test, forming a blue precipitate of Prussian blue.

3. Nitriles: Nitriles are organic compounds that contain a carbon triple bond to a nitrogen atom (C≡N). Nitriles do not respond positively to the Lassaigne test for nitrogen. Instead, they produce a yellow precipitate of sodium sulfocyanide (NaSCN) due to the reaction between sodium cyanide and sulfur present in the test reagents.

4. Nitro compounds: Nitro compounds contain a nitro group (-NO2) bonded to a carbon atom. Nitro compounds do not respond positively to the Lassaigne test for nitrogen. Instead, they produce a yellow precipitate of sodium sulfocyanide (NaSCN) similar to nitriles.

Based on the information above, the nitrogen-containing compound that does not respond positively to the Lassaigne test for nitrogen is nitriles.

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