The compound x has molecular formula C6H7N and becomes soluble in dilute mineral acid, indicating that it is a basic amine.
On treatment with CHCl3 and alcoholic KOH, compound x gives a foul-smelling product y. This is the carbylamine test, which is given only by primary amines.
Hence, x is a primary amine. The only aromatic primary amine with molecular formula C6H7N is aniline (C6H5NH2).
Aniline reacts with benzenesulphonyl chloride in the Hinsberg test to form a sulphonamide z, which is soluble in alkali due to the presence of acidic N–H hydrogen.
The structure of compound z is:
C6H5–SO2–NH–C6H5
Now, count the number of different (chemically non-equivalent) hydrogen atoms in compound z.
Each benzene ring in z is a monosubstituted phenyl ring. In a monosubstituted benzene ring, aromatic hydrogens fall into three distinct environments:
• Ortho hydrogens (2 equivalent)
• Meta hydrogens (2 equivalent)
• Para hydrogen (1)
Thus, each monosubstituted phenyl ring contributes 3 different aromatic H types.
Since there are two monosubstituted phenyl rings:
$$ 3 + 3 = 6 $$
Additionally, there is one N–H hydrogen.
Therefore, total number of different hydrogen atoms:
$$ 6 + 1 = 7 $$
Hence, the correct answer is 7.
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