S - Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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61.
Which of the following reactions is not a part of Solvay's process for preparation of sodium carbonate?
A
$$2N{H_3} + {H_2}O + C{O_2} \to {\left( {N{H_4}} \right)_2}C{O_3}$$
62.
The alkaline earth metal nitrate that does not crystallise with water molecules, is:
A
$$Mg{\left( {N{O_3}} \right)_2}$$
B
$$Sr{\left( {N{O_3}} \right)_2}$$
C
$$Ca{\left( {N{O_3}} \right)_2}$$
D
$$Ba{\left( {N{O_3}} \right)_2}$$
Answer :
$$Ba{\left( {N{O_3}} \right)_2}$$
The chances of formation of hydrate decreases with the decrease in the charge density down the group. This is why, $$Ba{\left( {N{O_3}} \right)_2}$$ does not crystallise with water molecules.
63.
Sodium carbonate solution in water is alkaline due to
A
hydrolysis of $$N{a^ + }$$
B
hydrolysis of $$CO_3^{2 - }$$
C
hydrolysis of both $$N{a^ + }$$ and $$CO_3^{2 - }\,ions$$
D
None of these
Answer :
hydrolysis of $$CO_3^{2 - }$$
Due to anionic hydrolysis
$$CO_3^{2 - } + {H_2}O \rightleftharpoons HCO_3^ - { + ^ - }OH$$
64.
Which of the following alkali metals when burnt in air forms a mixture of oxide as well as nitride?
A
$$K$$
B
$$Na$$
C
$$Li$$
D
$$Cs$$
Answer :
$$Li$$
Lithium when burnt in air forms a mixture of oxide as well as nitride.
$$4Li + {O_2} \to 2L{i_2}O;$$ $$6Li + {N_2} \to 2L{i_3}N$$
65.
The stability of $${K_2}O,{K_2}{O_2}$$ and $$K{O_2}$$ is in order $${K_2}O,{K_2}{O_2} < K{O_2}.$$ This increasing stability as the size of metal ion increases is due to stabilisation of
A
larger cation by smaller anions through lattice energy effects
B
larger cation by larger anions through lattice energy effects
C
smaller cations by smaller anions through melting point
D
smaller cations by larger anions through melting point.
Answer :
larger cation by larger anions through lattice energy effects
No explanation is given for this question. Let's discuss the answer together.
66.
Which of the following oxides of potassium is not known ?
A
$${K_2}O$$
B
$${K_2}{O_4}$$
C
$$K{O_3}$$
D
$${K_2}{O_3}$$
Answer :
$${K_2}{O_4}$$
$$O_4^{2 - }\,ion$$ is not possible and $${K_2}{O_4}$$ is unknown.
67.
The order solubility in water of alkaline earth metal sulphates down the group is $$Be > Mg > Ca > Sr > Ba.$$ This is due to increases in
A
ionization energy
B
melting point
C
coordination number
D
All of these
Answer :
coordination number
In crystalline sulphates, the coordination number of the ions increases from $$Be$$ to $$Ba$$ and so also the lattice energy hence solubility in $${H_2}O$$ decreases.
68.
$$N{a_2}S{O_3}$$ and $$NaHC{O_3}$$ may be distinguished by treating their aqueous solution with :
69.
An unknown inorganic compound $$(X)$$ loses its water of crystallization on heating and its aqueous solution gives the following reactions :
(i) It gives a white turbidity with dilute $$HCl$$ solution
(ii) It decolourises a solution of iodine in potassium iodide
(iii) It gives a white precipitate with silver nitrate solution which turns black on standing.
Identify the compound $$(X)$$