S - Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
Learn S - Block Elements MCQ questions & answers in Inorganic Chemistry are available for students perparing for IIT-JEE, NEET, Engineering and Medical Enternace exam.
121.
First ionisation energy of alkali metals is very low but second ionisation energy is very high because
A
alkali metals acquire noble gas configuration after losing one electron
B
a large amount of energy is required to remove electron from a cation
C
alkali metals can form only univalent ions
D
first group elements can lose only one electron
Answer :
alkali metals acquire noble gas configuration after losing one electron
No explanation is given for this question. Let's discuss the answer together.
122.
Match the column I with column II and mark the appropriate choice.
Column I
Column II
a.
$$N{a^ + }$$
1.
Chlorophyll
b.
$${K^ + }$$
2.
Bones and teeth
c.
$$C{a^{2 + }}$$
3.
Regulating flow of water across cell membrane
d.
$$M{g^{2 + }}$$
4.
Activation of enzyme within cell fluids
A
a - 1, b - 3, c - 2, d - 4
B
a - 4, b - 3, c - 2, d - 1
C
a - 1, b - 2, c - 3, d - 4
D
a - 3, b - 4, c - 2, d - 1
Answer :
a - 3, b - 4, c - 2, d - 1
No explanation is given for this question. Let's discuss the answer together.
123.
Match the column I with column II and mark the appropriate choice.
Column I
Column II
a.
$$Na$$
1.
Crimson red
b.
$$K$$
2.
Yellow
c.
$$Sr$$
3.
Apple green
d.
$$Ba$$
4.
Violet
A
a - 1, b - 2, c - 3, d - 4
B
a - 2, b - 4, c - 1, d - 3
C
a - 4, b - 3, c - 2, d - 1
D
a - 3, b - 4, c - 1, d - 2
Answer :
a - 2, b - 4, c - 1, d - 3
No explanation is given for this question. Let's discuss the answer together.
124.
A compound of sodium does not give $$C{O_2}$$ when heated but it gives $$C{O_2}$$ when treated with dilute acids. A crystalline compound is found to have $$37.1\% \,Na$$ and $$14.52\% \,{H_2}O.$$ Hence, compound is
A
$$N{a_2}C{O_3} \cdot {H_2}O$$
B
$$NaHC{O_3} \cdot 5{H_2}O$$
C
$$N{a_2}C{O_3} \cdot 10{H_2}O$$
D
$$NaHC{O_3} \cdot 10{H_2}O$$
Answer :
$$N{a_2}C{O_3} \cdot {H_2}O$$
$$C{O_2}$$ is obtained only when the compound is decomposed by acid thus, it is $$N{a_2}C{O_3}.$$ It cannot be $$NaHC{O_3}$$ since, it gives $$C{O_2}$$ on heating.
Probable compound is $$\mathop {N{a_2}C{O_3}}\limits_{85.48\% } \cdot \mathop {x{H_2}O}\limits_{14.52\% } $$
125.
Which one is the correct statement with reference to solubility of $$MgS{O_4}$$ in water?
A
$$SO_4^{2 - }\,ion$$ mainly contributes towards hydration energy.
B
Sizes of $$M{g^{2 + }}$$ and $$SO_4^{2 - }$$ are similar.
C
Hydration energy of $$MgS{O_4}$$ is higher in comparison to its lattice energy.
D
Ionic potential (charge/radius ratio) of $$M{g^{2 + }}$$ is very low.
Answer :
Hydration energy of $$MgS{O_4}$$ is higher in comparison to its lattice energy.
$$MgS{O_4}$$ is the only alkaline earth metal sulphate which is soluble in water and for solubility hydration energy should be greater than lattice energy.
126.
Which of the following on thermal decomposition yields a basic as well as acidic oxide?
A
$$NaN{O_3}$$
B
$$KCl{O_3}$$
C
$$CaC{O_3}$$
D
$$N{H_4}N{O_3}$$
Answer :
$$CaC{O_3}$$
Calcium carbonate on thermal decomposition gives $$CaO$$ (Basic oxide) and $$C{O_2}$$ (Acidic oxide)
\[CaC{{O}_{3}}\xrightarrow{\Delta }\underset{\text{Basic oxide }}{\mathop{CaO}}\,+\underset{\text{Acidic oxide }}{\mathop{C{{O}_{2}}\uparrow }}\,\]
127.
The hydration energy of $$M{g^{ + + }}$$ is larger than that of :
A
$$A{l^{3 + }}$$
B
$$N{a^ + }$$
C
$$B{e^{ + + }}$$
D
$$M{g^{3 + }}$$
Answer :
$$N{a^ + }$$
$$N{a^ + }$$ ion has larger size than $$M{g^{2 + }}$$ ion and hence hydration energy of $$M{g^{2 + }}$$ is larger than that of $$N{a^ + }$$.
128.
Washing soda has formula
A
$$N{a_2}C{O_3} \cdot 7{H_2}O$$
B
$$N{a_2}C{O_3} \cdot 10{H_2}O$$
C
$$N{a_2}C{O_3} \cdot 3{H_2}O$$
D
$$N{a_2}C{O_3}$$
Answer :
$$N{a_2}C{O_3} \cdot 10{H_2}O$$
Washing soda is chemicaly named as sodium carbonate decahydrate, so its formula is $$N{a_2}C{O_3} \cdot 10{H_2}O.$$
129.
Melting point of calcium halides decreases in the order