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20
MCQ (Single Correct Answer)

Although zirconium belongs to 4 d transition series and hafniun to 5 d transition series even then they show similar physical and chemical properties because ............ .

A
both belong to $d$-block
B
both have same number of electrons
C
both have similar atomic radius
D
both belong to the same group of the Periodic Table
21
MCQ (Single Correct Answer)

Why is HCl not used to make the medium acidic in oxidation reactions of $\mathrm{KMnO}_4$ in acidic medium?

A
Both HCl and $\mathrm{KMnO}_4$ act as oxidising agents
B
$\mathrm{KMnO}_4$ oxidises HCl into $\mathrm{Cl}_2$ which is also an oxidising agent
C
$\mathrm{KMnO}_4$ is a weaker oxidising agent than HCl
D
$\mathrm{KMnO}_4$ acts as a reducing agent in the presence of HCl
22
MCQ (Multiple Correct Answer)

Generally transition elements and their salts are coloured due to the presence of unpaired electrons in metal ions. Which of the following compounds are coloured?

A
$\mathrm{KMnO}_4$
B
$\mathrm{Ce}\left(\mathrm{SO}_4\right)_2$
C
$\mathrm{TiCl}_4$
D
$\mathrm{Cu}_2 \mathrm{Cl}_2$
23
MCQ (Multiple Correct Answer)

Transition elements show magnetic moment due to spin and orbital motion of electrons. Which of the following metallic ions have almost same spin only magnetic moment?

A
$\mathrm{Co}^{2+}$
B
$\mathrm{Cr}^{2+}$
C
$\mathrm{Mn}^{2+}$
D
$\mathrm{Cr}^{3+}$
24
MCQ (Multiple Correct Answer)

In the form of dichromate, $\mathrm{Cr}(\mathrm{VI})$ is a strong oxidising agent in acidic medium but $\mathrm{Mo}(\mathrm{VI})$ in $\mathrm{MoO}_3$ and W (VI) in $\mathrm{WO}_3$ are not because

A
$\mathrm{Cr}(\mathrm{VI})$ is more stable than $\mathrm{Mo}(\mathrm{VI})$ and $\mathrm{W}(\mathrm{VII})$.
B
$\mathrm{Mo}(\mathrm{VI})$ and $\mathrm{W}(\mathrm{VI})$ are more stable than $\mathrm{Cr}(\mathrm{VI})$.
C
Higher oxidation states of heavier members of group-6 of transition series are more stable.
D
Lower oxidation states of heavier members of group-6 of transition series are more stable.
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