1. \[AlCl_{3}\] on hydrolysis gives
a) \[Al_{2}O_{3}.H_{2}O\]
b) \[Al\left(OH\right)_{3} \]
c) \[Al_{2}O_{3}\]
d) \[AlCl_{3}.6H_{2}O\]
Explanation: \[Al\left(OH\right)_{3} \]
2. Which is not correct?
a) Al acts as a reducing agent
b) Al does not react with steam even at higher temperature
c) Al forms a number of alloys with other metals
d) Al is ionic in all its compounds
Explanation: "Al is ionic in all its compounds". This is incorrect.
3. Ionisation enthalpy ( \[\triangle\] i H1kJ mol–1) for the elements of Group 13 follows the order
a) B > Al > Ga > In > Tl
b) B < Al < Ga < In < Tl
c) B < Al > Ga < In > Tl
d) B > Al < Ga > In < Tl
Explanation: B > Al < Ga > In < Tl
4. The state of hybridization of B in \[BCI_{3} \] is
a) \[sp^{3}\]
b) \[sp^{2}\]
c) sp
d) \[sp^{3}d^{2}\]
Explanation: \[sp^{2}\]
5. The type of hybridization of boron in diborane is
a) sp
b) \[sp^{2}\]
c) \[sp^{3}\]
d) \[sp^{3}d^{2}\]
Explanation: \[sp^{3}\]
6. Specify the coordination geometry around and hybridization of N and B atoms in a 1: 1 complex of \[BF_{3}\] and \[NH_{3}\]
a) N : tetrahedral, \[sp^{3}\] ; B : tetrahedral, \[sp^{3}\]
b) N : pyramidal, \[sp^{3}\] ; B : pyramidal, \[sp^{3}\]
c) N : pyramidal, \[sp^{3}\] ; B : planar, \[sp^{3}\]
d) N : pyramidal, \[sp^{3}\] ; B : tetrahedral, \[sp^{3}\]
Explanation: N : tetrahedral, \[sp^{3}\] ; B : tetrahedral, \[sp^{3}\]
7. Which one of the following elements has the highest melting
point ?
a) Boron
b) Aluminium
c) Gallium
d) Thallium
Explanation: Boron has a giant molecule structure like that of diamond therefore it has highest melting point
8. The element which shows least metallic character is
a) Indium
b) Boron
c) Aluminium
d) Gallium
Explanation: Boron
9. Which of the following does not form \[M^{3+}\] ion?
a) Boron
b) Aluminium
c) Indium
d) Gallium
Explanation: Due to its small size and high ionization energy boron does not form B3+ ion
10. Which of the following does not react with aqueous
NaOH ?
a) B
b) Al
c) Ga
d) Tl
Explanation: 'B'