17
MCQ (Single Correct Answer)
Which of the following statements is not correct?
A
Copper liberates hydrogen from acids
B
In its higher oxidation states, manganese forms stable compounds with oxygen and fluorine
C
$\mathrm{Mn}^{3+}$ and $\mathrm{Co}^{3+}$ are oxidising agents in aqueous solution
D
$\mathrm{Ti}^{2+}$ and $\mathrm{Cr}^{2+}$ are reducing agents in aqueous solution
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