Amines

Nitrobenzene on nitration gives dinitro benzene as group is meta-directing. In this reaction the attacking reagent is

Nitrobenzene has the smell of bitter almonds. Benzaldehyde is commonly called the oil of bitter almonds and also has the smell of bitter almonds.

-methyl- -pentanamine is a secondary amine because it contains amino-group

Gabriel synthesis is used for the preparation of primary amines. Butylamine, isobutylamine and -phenyl ethylamine are primary amine hence these can be prepared by Gabriel's synthesis but -methyl benzylamine is a secondary amine and therefore, it cannot be prepared by Gabriel's synthesis.

The chromophore group in the final compound is azo group

This reaction is also termed as Hermann's bromamide reaction.

Answer (a) Hinsberg?s reagent

Hoffmann bromaraide reaction converts acid amides to primary amines :
1^{\circ}
The amine formed has one carbon atom lesser than that present in acid amide

Step 1: Oxidation of Aniline
Aniline (C H NH ) undergoes oxidation with potassium dichromate (K Cr O ) in sulfuric acid (H SO ) to form nitrobenzene (C H NO ).
Step 2: Explanation of Other Options
Option (a) phenylhydroxylamine is incorrect because this is not the product of oxidation.
Option (b) p-benzoquinone is incorrect because quinones are not produced in this oxidation.

Option (c) nitrosobenzene is incorrect because nitroso compounds are not produced in this reaction.

Step 3: Conclusion Thus, the oxidation of aniline with K Cr O /H SO gives nitrobenzene.

Step 1: Methylamine as a Base
Methylamine (CH NH ) is a stronger base than ammonia (NH ) because the methyl group (CH ) is an electron-donating group, which increases the electron density on nitrogen and makes it more readily available to accept protons.
Step 2: Explanation of Other Options
Option (b) is incorrect because methylamine is a stronger base than ammonia.

Option (c) is incorrect because methylamine is not acidic, it is basic.
Option (d) is incorrect because both methylamine and ammonia can form salts with acids, but this does not affect their basicity directly.

Step 3: Conclusion
Thus, methylamine is a stronger base than NH .