JEE Main 2017 — Chemistry Inorganic Chemistry

2017mcqmedium

The correct sequence of decreasing number of $\pi$ -bonds in the structure of ${H}_{2}S{O}_{3}, {H}_{2}S{O}_{4}$ and ${H}_{2}{S}_{2}{O}_{7}$ is:

Official previous-year question

Held on 9 Apr 2017 · Verified 6 Jul 2026.

Options

A
${\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}>{\text{H}}_{2}\text{S}{\text{O}}_{3}>{\text{H}}_{2}\text{S}{\text{O}}_{4}$
B
${\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}>{\text{H}}_{2}\text{S}{\text{O}}_{4}>{\text{H}}_{2}\text{S}{\text{O}}_{3}$
C
${\text{H}}_{2}\text{S}{\text{O}}_{4}>{\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}>{\text{H}}_{2}\text{S}{\text{O}}_{3}$
D
${\text{H}}_{2}\text{S}{\text{O}}_{3}>{\text{H}}_{2}\text{S}{\text{O}}_{4}>{\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}$

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Solution

Number of $\pi$ -bonds

${H}_{2}{S}_{2}{O}_{7}=\mathrm{HO}-\underset{O}{\overset{O}{\underset{||}{\overset{||}{S}}}}-O-\underset{O}{\overset{O}{\underset{||}{\overset{||}{S}}}}-\mathrm{OH}$ $4$

${H}_{2}{\mathrm{So}}_{4}=\mathrm{OH}-\underset{O}{\overset{O}{\underset{||}{\overset{||}{S}}}}-\mathrm{OH}$ $2$

${H}_{2}{\mathrm{SO}}_{3}=\mathrm{HO}-\underset{O}{\underset{||}{\overset{..}{S}}}-\mathrm{OH}$ $1$

Therefore, the correct sequence of decreasing number of pi-bonds is ${H}_{2}{S}_{2}{O}_{7}(4)>{H}_{2}{\mathrm{SO}}_{4}(2)>{H}_{2}{\mathrm{SO}}_{3}(1)$ . The numbers in bracket indicate the number of pi bonds.

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Options

${\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}>{\text{H}}_{2}\text{S}{\text{O}}_{3}>{\text{H}}_{2}\text{S}{\text{O}}_{4}$

${\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}>{\text{H}}_{2}\text{S}{\text{O}}_{4}>{\text{H}}_{2}\text{S}{\text{O}}_{3}$

${\text{H}}_{2}\text{S}{\text{O}}_{4}>{\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}>{\text{H}}_{2}\text{S}{\text{O}}_{3}$

${\text{H}}_{2}\text{S}{\text{O}}_{3}>{\text{H}}_{2}\text{S}{\text{O}}_{4}>{\text{H}}_{2}{\text{S}}_{2}{\text{O}}_{7}$

Solution

Number of $\pi$ -bonds

${H}_{2}{S}_{2}{O}_{7}=\mathrm{HO}-\underset{O}{\overset{O}{\underset{||}{\overset{||}{S}}}}-O-\underset{O}{\overset{O}{\underset{||}{\overset{||}{S}}}}-\mathrm{OH}$ $4$

${H}_{2}{\mathrm{So}}_{4}=\mathrm{OH}-\underset{O}{\overset{O}{\underset{||}{\overset{||}{S}}}}-\mathrm{OH}$ $2$

${H}_{2}{\mathrm{SO}}_{3}=\mathrm{HO}-\underset{O}{\underset{||}{\overset{..}{S}}}-\mathrm{OH}$ $1$

JEE Main 2017 — Chemistry Inorganic Chemistry

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JEE Main 2017 — Chemistry Inorganic Chemistry

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JEE Main Inorganic Chemistry in other years

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Physical Chemistry

Organic Chemistry

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