JEE CHEMISTRY MCQ: S-BLOCK ELEMENTS

1 Easy

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Analyzing +4 | -1

Assertion (A) :

\mathrm{KO}_2

is paramagnetic.

Reason (R) :

\mathrm{K}^{+}

ion has unpaired electron.

View answer and explanation

Correct option: C

\mathbf{A}

is true but

\mathbf{R}

is false.

The correct answer is C because KO2 is paramagnetic due to the presence of an unpaired electron in the superoxide ion (O2-), but K+ ion does not have unpaired electrons.

More Questions from S-BLOCK ELEMENTS

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Assertion (A): Among the alkali metals, lithium salts exhibit the least electrical condutance in aqueous solutions.
Reason (R): Smaller the radius of the hydrated cation, lower is the electrical conductance in aqueous solutions.

(A)

is a ternary salt with divalent cation.

(A)

gives yellow ppt. with

\mathrm{K}_2 \mathrm{CrO}_4

as well as with

\mathrm{AgNO}_3

. (A) is precipitated by

\mathrm{H}_2 \mathrm{~S}

neither in acidic nor ammoniacal medium, but addition of

\left(\mathrm{NH}_4\right)_2 \mathrm{CO}_3

\mathrm{NH}_4 \mathrm{OH}

gave white ppt. (B).

0.297 \mathrm{~g}

(A)

gave

0.197 \mathrm{~g}

(B)

. Identify

(A)

. In the Down’s cell

\mathrm{KCl}

is added in

\mathrm{NaCl}

to: Which of the alkali metal is having least melting point? Fusion mixture is comprised of: Statement 1:

{LiCl}

is predominatly a covalent compound.

Statement 2: Electronegativity difference between

{Li}

and

{Cl}

is too small.