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18
MCQ (Single Correct Answer)

When acidified $\mathrm{K}_2 \mathrm{Cr}_2 \mathrm{O}_7$ solution is added to $\mathrm{Sn}^{2+}$ salt then $\mathrm{Sn}^{2+}$ changes to

A
$\mathrm{Sn}$
B
$\mathrm{Sn}^{3+}$
C
$\mathrm{Sn}^{4+}$
D
$\mathrm{Sn}^{+}$
19
MCQ (Single Correct Answer)

Highest oxidation state of manganese in fluoride is $+4\left(\mathrm{MnF}_4\right)$ but highest oxidation state in oxides is $+7\left(\mathrm{Mn}_2 \mathrm{O}_7\right)$ because

A
fluorine is more electronegative than oxygen
B
fluorine does not possess $d$ orbitals
C
fluorine stabilises lower oxidation state
D
in covalent compounds, fluorine can form single bond only while oxygen forms double bond
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
$\mathrm{Cu}_2 \mathrm{Cl}_2$
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