P - Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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331.
One mole of fluorine is reacted with two moles of hot and concentrated $$KOH.$$ The products formed are $$KF,{H_2}O$$ and $${O_2}.$$ The molar ratio of $$KF,{H_2}O$$ and $${O_2}$$ respectively is
A
1 : 1 : 2
B
2 : 1 : 0.5
C
1 : 2 : 1
D
2 : 1 : 2
Answer :
2 : 1 : 0.5
$$2{F_2} + 4KOH \to 4KF + {O_2} + 2{H_2}O$$ for 1 $$mole$$ of $${F_2}$$ the molar ratio.
$$\eqalign{
& {F_2}\,\,\,\,\,\,KOH\,\,\,\,\,\,KF\,\,\,\,\,\,{O_2}\,\,\,\,\,\,{H_2}O \cr
& 1\,\,\,\,\,\,\,\,\,\,\,\,\,2\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,2\,\,\,\,\,\,\,\,\,\,\frac{1}{2}\,\,\,\,\,\,\,\,\,\,\,\,1 \cr} $$
332.
Which one of the following does not have a pyramidal shape ?
A
$${\left( {C{H_3}} \right)_3}N$$
B
$${\left( {Si{H_3}} \right)_3}N$$
C
$$P{\left( {C{H_3}} \right)_3}$$
D
$$P{\left( {Si{H_3}} \right)_3}$$
Answer :
$${\left( {Si{H_3}} \right)_3}N$$
In case of $$N{\left( {Si{H_3}} \right)_3},N$$ atom is $$s{p^2}$$ hybridised, the lone pair is present in $$2p$$ orbital and it is transferred to empty $$d$$ orbital of $$Si$$ forming $$d\pi - p\pi $$ bond. Hence nitrogen with $$s{p^2}$$ hybridization has trigonal planar shape.
333.
Which of the following reactions is an example of a redox reaction?
334.
An element $$\left( X \right)$$ forms compounds of the formula $$XC{l_3},{X_2}{O_5}$$ and $$C{a_3}{X_2}$$ but does not form $$XC{l_5}.$$ Which of the following is the element $$X?$$
A
$$B$$
B
$$Al$$
C
$$N$$
D
$$P$$
Answer :
$$N$$
Nitrogen can form $$NC{l_3},{N_2}{O_5}C{a_3}{N_2}$$ and not $$NC{l_5}$$ since it has no $$d$$ atomic orbitals in valence shell
335.
$${P_4}{O_{10}}$$ is not used to dry $$N{H_3}$$ gas because
A
$${P_4}{O_{10}}$$ reacts with moisture in $$N{H_3}.$$
B
$${P_4}{O_{10}}$$ is not a drying agent.
C
$${P_4}{O_{10}}$$ is acidic and $$N{H_3}$$ is basic.
D
$${P_4}{O_{10}}$$ is basic and $$N{H_3}$$ is acidic.
Answer :
$${P_4}{O_{10}}$$ is acidic and $$N{H_3}$$ is basic.
336.
$$\eqalign{
& A + {H_2}O \to B + HCl \cr
& B + {H_2}O \to C + HCl \cr} $$
Compound $$(A), (B)$$ and $$(C)$$ will be respectively :
A
$$PC{l_5},POC{l_3},{H_3}P{O_3}$$
B
$$PC{l_5},POC{l_3},{H_3}P{O_4}$$
C
$$SOC{l_2},POC{l_3},{H_3}P{O_3}$$
D
$$PC{l_3},POC{l_3},{H_3}P{O_4}$$
Answer :
$$PC{l_5},POC{l_3},{H_3}P{O_4}$$
$$\eqalign{
& \mathop {PC{l_5}}\limits_{\left( A \right)} + {H_2}O \to \mathop {POC{l_3}}\limits_{\left( B \right)} + 2HCl \cr
& \mathop {POC{l_3}}\limits_{\left( B \right)} + 3{H_2}O \to \mathop {{H_3}P{O_4}}\limits_{\left( C \right)} + 3HCl \cr} $$
337.
The element which exists in liquid state for a wide range of temperature and can be used for measuring high temperature is
A
$$B$$
B
$$Al$$
C
$$Ga$$
D
$$In$$
Answer :
$$Ga$$
Gallium $$(Ga)$$ with unusually low melting point $$\left( {303\,K} \right),$$ can exist in liquid state during summer. Its high boiling point $$\left( {2676\,K} \right)$$ makes it a useful material for measuring high temperature.
338.
Borax is converted into crystalline boron by the following steps :
\[\text{Borax}\xrightarrow{X}{{H}_{3}}B{{O}_{3}}\xrightarrow{\Delta }{{B}_{2}}{{O}_{3}}\xrightarrow[\Delta ]{Y}B\]
$$X$$ and $$Y$$ are respectively :
Due to the inert pair effect ( the reluctance of $$n{s^2}$$ electrons of outermost shell to participate in bonding ) the stability of $${M^{2 + }}$$ ions ( of group 14 elements ) increases as we go down the group.