S - Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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31.
In the following sequence of reaction, identify the compounds $$(A), (B), (C)$$ and $$(D) :$$
\[\underset{\text{Solution}}{\mathop{N{{a}_{2}}C{{O}_{3}}}}\,\xrightarrow{S{{O}_{2}}}\left( A \right)\xrightarrow{N{{a}_{2}}C{{O}_{3}}}\] \[\left( B \right)\xrightarrow[\text{Heat}]{S}\left( C \right)\xrightarrow{AgN{{O}_{3}}}\left( D \right)\]
A
$$N{a_2}S{O_3},NaHS{O_3},N{a_2}S,A{g_2}S$$
B
$$NaHS{O_3},N{a_2}S{O_3},N{a_2}{S_2}{O_3},A{g_2}S$$
C
$$NaHS{O_3},N{a_2}S{O_4},N{a_2}S,A{g_2}O$$
D
$$N{a_2}S{O_3},N{a_2}S{O_4},N{a_2}{S_2}{O_3},Ag$$
\[\begin{align}
& N{{a}_{2}}C{{O}_{3}}+2S{{O}_{2}}+{{H}_{2}}O\to \underset{\left( A \right)}{\mathop{2NaHS{{O}_{3}}}}\,+C{{O}_{2}} \\
& \underset{\left( A \right)}{\mathop{2NaHS{{O}_{3}}}}\,+N{{a}_{2}}C{{O}_{3}}\to \underset{\left( B \right)}{\mathop{2N{{a}_{2}}S{{O}_{3}}}}\,+{{H}_{2}}O+C{{O}_{2}} \\
& \underset{\left( B \right)}{\mathop{2N{{a}_{2}}S{{O}_{3}}}}\,+S\xrightarrow{\text{Heat}}\underset{\left( C \right)}{\mathop{2N{{a}_{2}}{{S}_{2}}{{O}_{3}}}}\, \\
& N{{a}_{2}}{{S}_{2}}{{O}_{3}}+AgN{{O}_{3}}\to \underset{\left( D \right)}{\mathop{A{{g}_{2}}S}}\,+{{H}_{2}}S{{O}_{4}} \\
\end{align}\]
32.
The set representing the correct order of first ionization potential is
A
$$K > Na > Li$$
B
$$Be > Mg > Ca$$
C
$$B > C > N$$
D
$$Ge > Si > C$$
Answer :
$$Be > Mg > Ca$$
In going from top to bottom in a group, the first ionization potential decreases, thus $$Be > Mg > Ca$$
33.
Lithium salts are mostly hydrated like $$LiCl \cdot 2{H_2}O$$ due to
A
maximum ionisation enthalpy
B
maximum degree of hydration of $$L{i^ + }$$
C
maximum hygroscopic nature
D
maximum chemical reactivity
Answer :
maximum degree of hydration of $$L{i^ + }$$
$$L{i^ + }$$ has maximum degree of hydration due to smallest size in the group hence its salts are mostly hydrated.
34.
Amongst the following hydroxides, the one which has the lowest value of $${K_{sp}}$$ is :
A
$$Ca{\left( {OH} \right)_2}$$
B
$$Mg{\left( {OH} \right)_2}$$
C
$$Be{\left( {OH} \right)_2}$$
D
$$Ba{\left( {OH} \right)_2}$$
Answer :
$$Be{\left( {OH} \right)_2}$$
$$Be{\left( {OH} \right)_2}$$ is insoluble in water and thus has lower value of $${K_{sp}}.$$
35.
Which of the following statements is false ?
A
$$C{a^{2 + }}\,ions$$ are important in blood clotting
B
$$C{a^{2 + }}\,ions$$ are not important in maintaining the regular beating of the heart
C
$$M{g^{2 + }}\,ions$$ are important in the green parts of plants
D
$$M{g^{2 + }}\,ions$$ form a complex with $$ATP$$
Answer :
$$C{a^{2 + }}\,ions$$ are not important in maintaining the regular beating of the heart
$$ \bullet \,\,C{a^{2 + }}\,ions$$ are very important factor in blood clotting.
$$ \bullet \,\,C{a^{2 + }}\,ions$$ are very important for maintaining the regular heart beating.
$$ \bullet\, \,M{g^{2 + }}\,ions$$ is present in the green parts of plants i.e., chlorophyll.
$$ \bullet \,\,M{g^{2 + }}$$ can form a complex with $$ATP.$$
No explanation is given for this question. Let's discuss the answer together.
37.
Bleaching powder is obtained by the action of chlorine gas and
A
dilute solution of $$Ca{\left( {OH} \right)_2}$$
B
concentrated solution of $$Ca{\left( {OH} \right)_2}$$
C
dry $$CaO$$
D
dry slaked lime
Answer :
dry slaked lime
Bleaching powder is prepared by passing chlorine gas over dry slaked lime $$Ca{\left( {OH} \right)_2}$$ by Hesenclaver method or by Bachmann method.
$$Ca{\left( {OH} \right)_2} + C{l_2} \to CaOC{l_2} + {H_2}O$$
38.
Which one of the following is present as an active ingredient in bleaching powder for
bleaching action ?
A
$$Ca{\left( {OCl} \right)_2}$$
B
$$Ca{O_2}C{l_2}$$
C
$$CaC{l_2}$$
D
$$CaOC{l_2}$$
Answer :
$$Ca{\left( {OCl} \right)_2}$$
$$Ca{\left( {OCl} \right)_2},$$ calcium hypochlorite is the active ingredient in bleaching powder which releases chlorine.