91. A chloride dissolves appreciably in cold water. When placed on a $$Pt$$ wire in bunsen flame, no distinctive colour is noted. Which cation could be present ?
A
$$B{e^{2 + }}$$
B
$$B{a^{2 + }}$$
C
$$P{b^{2 + }}$$
D
$$C{a^{2 + }}$$
Answer :
$$B{e^{2 + }}$$
92. Which one of the following atoms will have the smallest size ?
A
$$Mg$$
B
$$Na$$
C
$$Be$$
D
$$Li$$
Answer :
$$Be$$
93. $$BeO$$ is insoluble but $$BaO$$ is soluble as
A
lattice energy of $$BeO$$ is higher than $$BaO$$ due to small size of $$B{e^{2 + }}$$ ion and its covalent nature
B
hydration energy of $$BeO$$ is lower than $$BaO$$ due to small size $$B{e^{2 + }}$$ ion
C
$$BeO$$ is amphoteric in nature while $$BaO$$ is basic
D
$$BeO$$ forms hydrated salts while $$BaO$$ forms anhydrous salts
Answer :
lattice energy of $$BeO$$ is higher than $$BaO$$ due to small size of $$B{e^{2 + }}$$ ion and its covalent nature
94. Which of the following atoms has the highest first ionization energy?
A
$$K$$
B
$$Sc$$
C
$$Rb$$
D
$$Na$$
Answer :
$$Sc$$
95. Which of the following statements is correct ?
A
Sodium carbonate decomposes on heating.
B
Sodium bicarbonate is more soluble in water than potassium bicarbonate.
C
Sodium when heated with excess of $${O_2},$$ gives peroxide.
D
Lithium halides are highly ionic in nature.
Answer :
Sodium when heated with excess of $${O_2},$$ gives peroxide.
96. $$M{g_2}{C_3}$$ reacts with water forming propyne gas. $$C_3^{4 - }\,ions$$ has :
A
two sigma and two $$pi$$ bonds
B
three sigma and one $$pi$$ bond
C
two sigma and one $$pi$$ bond
D
two sigma and three $$pi$$ bonds
Answer :
two sigma and two $$pi$$ bonds
97.
Fill up the blanks with appropriate choices.
Lithium and magnesium react slowly with water. Their hydroxides are $$\underline {\left( {\text{i}} \right)} $$ soluble in water. Carbonates of $$Li$$ and $$Mg$$ $$\underline {\left( {{\text{ii}}} \right)} $$ easily on heating. Both $$LiCl$$ and $$MgC{l_2}$$ are $$\underline {\left( {{\text{iii}}} \right)} $$ in ethanol and are $$\underline {\left( {{\text{iv}}} \right)} .$$ They crystallise from their aqueous solutions as $$\underline {\left( {\text{v}} \right)} .$$
| (i) | (ii) | (iii) | (iv) | (v) | |
| (a) | more | do not decompose | soluble | hygroscopic | hydrates |
| (b) | less | decompose | soluble | deliquescent | hydrates |
| (c) | freely | sublime | insoluble | deliquescent | anhydrous |
| (d) | freely | decompose | soluble | hygroscopic | crystals |
A
(a)
B
(b)
C
(c)
D
(d)
Answer :
(b)
98. The order of solubility of lithium halides in non polar solvents follows the order
A
$$LiI > LiBr > LiCl > LiF$$
B
$$LiF > LiI > LiBr > LiCl$$
C
$$LiCl > LiF > LiI > LiBr$$
D
$$LiBr > LiCl > LiF > LiI$$
Answer :
$$LiI > LiBr > LiCl > LiF$$
99. Which one of the following properties of alkali metals increases in magnitude as the atomic number rises ?
A
lonic radius
B
Melting point
C
Electronegativity
D
First ionisation energy
Answer :
lonic radius
100. Which one is the correct statement with reference to the solubility of $$MgS{O_4}$$ in water ?
A
$$SO_4^{2 - }\,ions$$ 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
lonic 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