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The correct order of acid strength is -
A
$HClO_4 \lt HClO_3 \lt HClO_2 \lt HClO$
B
$HClO_2 \lt HClO_3 \lt HClO_4 \lt HClO$
C
$HClO_4 \lt HClO \lt HClO_2 \lt HClO_3$
D
$HClO \lt HClO_2 \lt HClO_3 \lt HClO_4$
Detailed Solution
Oxidation numbers of chlorine: HClO (+1), $HClO_2$ (+3), $HClO_3$ (+5), $HClO_4$ (+7).
As the oxidation number of the central atom increases, the number of oxygen atoms attached to it increases, and the O-H bond becomes more polar.
The conjugate bases are also stabilised more by the delocalisation of the negative charge over more oxygen atoms: $ClO^- \lt ClO_2^- \lt ClO_3^- \lt ClO_4^-$ in stability.
The more stable the conjugate base, the stronger the acid.
So the correct order of acid strength is $HClO \lt HClO_2 \lt HClO_3 \lt HClO_4$.
As the oxidation number of the central atom increases, the number of oxygen atoms attached to it increases, and the O-H bond becomes more polar.
The conjugate bases are also stabilised more by the delocalisation of the negative charge over more oxygen atoms: $ClO^- \lt ClO_2^- \lt ClO_3^- \lt ClO_4^-$ in stability.
The more stable the conjugate base, the stronger the acid.
So the correct order of acid strength is $HClO \lt HClO_2 \lt HClO_3 \lt HClO_4$.