NEET UG 2021 — Chemistry Inorganic Chemistry

2021mcqeasy

In which one of the following arrangements the given sequence is not strictly according to the properties indicated against it?

Official previous-year question

Held on 30 Apr 2021 · Verified 9 Jul 2026.

Options

A
$\mathrm{HF}<\mathrm{HCl}<\mathrm{HBr}<\mathrm{HI}:$ Increasing acidic strength
B
${H}_{2}O<{H}_{2}S<{H}_{2}\mathrm{Se}<{H}_{2}\mathrm{Te}:$ Increasing ${\mathrm{pK}}_{a}$ values
C
${\mathrm{NH}}_{3}<{\mathrm{PH}}_{3}<{\mathrm{AsH}}_{3}<{\mathrm{SbH}}_{3}:$ Increasing acidic character
D
${\mathrm{CO}}_{2}<{\mathrm{SiO}}_{2}<{\mathrm{SnO}}_{2}<{\mathrm{PbO}}_{2}:$ Increasing oxidizing power

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Solution

$1)$ $\mathrm{HF}<\mathrm{HCl}<\mathrm{HBr}<\mathrm{HI}$ bond strength decreases therefore, acidic strength increases.

$2)$ ${H}_{2}O<{H}_{2}S<{H}_{2}\mathrm{Se}<{H}_{2}\mathrm{Te}$ from going down the group bond length increase so bond strength decreases therefore, acidic nature of these will increase but ${\mathrm{pK}}_{a}$ will decrease.

So, this given order is wrong.

$3)$ ${\mathrm{NH}}_{3}<{\mathrm{PH}}_{3}<{\mathrm{AsH}}_{3}<{\mathrm{SbH}}_{3}$ from going down the group bond length increases, so bond strength decreases therefore, acidic nature of these will increase

$4)$ ${\mathrm{CO}}_{2}<{\mathrm{SiO}}_{2}<{\mathrm{SnO}}_{2}<{\mathrm{PbO}}_{2}$ From going down the group stability of higher oxidation state decreases due to inert pair effect therefore, their tendency to reduce will increase, so their oxidizing power will increase.

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Options

$\mathrm{HF}<\mathrm{HCl}<\mathrm{HBr}<\mathrm{HI}:$ Increasing acidic strength

${H}_{2}O<{H}_{2}S<{H}_{2}\mathrm{Se}<{H}_{2}\mathrm{Te}:$ Increasing ${\mathrm{pK}}_{a}$ values

${\mathrm{NH}}_{3}<{\mathrm{PH}}_{3}<{\mathrm{AsH}}_{3}<{\mathrm{SbH}}_{3}:$ Increasing acidic character

${\mathrm{CO}}_{2}<{\mathrm{SiO}}_{2}<{\mathrm{SnO}}_{2}<{\mathrm{PbO}}_{2}:$ Increasing oxidizing power

Solution

$1)$ $\mathrm{HF}<\mathrm{HCl}<\mathrm{HBr}<\mathrm{HI}$ bond strength decreases therefore, acidic strength increases.

So, this given order is wrong.

NEET UG 2021 — Chemistry Inorganic Chemistry

Options

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Solution

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NEET UG 2021 — Chemistry Inorganic Chemistry

Options

Did you get this right?

Solution

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NEET UG Inorganic Chemistry in other years

More NEET UG Inorganic Chemistry questions

Other Chemistry topics for NEET UG

Physical Chemistry

Organic Chemistry

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