P Block (XI)

Question 1

The decrease in stability of higher oxidation state in p block with increasing atomic number is due to

Answer 1

Inert pair effect:
The reluctance of s-subshell electrons to participate in bonding

Question 2

Oxidation state shown by group 13 elements

Answer 2

+1 and +3

Question 3

Aluminum is more reactive than iron. But aluminium is less easily corroded than iron because

Answer 3

Oxygen forms a protective oxide layer on aluminium surface

Question 4

GeO is acidic. True or false

Answer 4

True

Question 5

Name an amphoteric oxide

Answer 5

SnO2

Question 6

In diamond, hybridization of carbon is

Answer 6

sp³ hybridization

Question 7

Graphite is a soft solid lubricant extremely difficult to melt. The reason for this anomalous behavior is that graphite

Answer 7

has carbon atoms arranged in large plates of rings of strongly bound carbon atoms with weak interplate bonds

Question 8

Graphite has:

Answer 8

• 2D structure
• van der waals forces between different layers
• sp² hybridised carbon linked with other three C atoms in hexagonal planar shape

Question 9

The most stable form of carbon

Answer 9

Graphite

Question 10

Number of 5 membered and 6 memebered rings in C60 molecule are respectively

Answer 10

12 and 20

Question 11

How many isotopes does boron have

Answer 11

2

Question 12

Which is incorrect :

A) Boron has two isotopes

B) Aluminium is the most abundant metal in earth crust

C) Order of ionisation enthalpy : B > TI > Ga > AI > In

D) Order of melting point: B>A|>T|>| n > Ga

Question 13

Most abundant metal in earth’s crust

Answer 13

Aluminium

Question 14

Order of ionisation enthalpy in group 13

Answer 14

Boron (B)>Thallium (Tl)>Gallium (Ga)>Aluminum (Al)>Indium (In)

Question 15

Order of melting point of group 13

Answer 15

Boron > Aluminum > Thallium > Indium > Gallium

Question 16

Specify the coordination geometry around and hybridisation of N and B atoms in 1: 1 complex of BCI, and NH3

Answer 16

N- tetrahedral sp³
B- tetrahedral sp³

Question 17

CCI4, is inert towards hydrolysis but SiCI4, is readily hydrolysed because

Answer 17

carbon cannot expand its octet but silicon can expand its octet

Question 18

The stability of dihalides of Si, Ge, Sn and Pb increases steadily in the sequence

Answer 18

SiX₂ < GeX₂ < SnX₂ < PbX₂

Question 19

Pb shows catenation. True or false

Answer 19

False

Question 20

The hybridisation of carbon in fullerenes

Answer 20

sp2

Question 21

Fullerenes are the pure form of carbon because

Answer 21

They have smooth structures without having dangling bonds

Question 22

Melting point of Ga in (K) is

Answer 22

303K

Question 23

Inter layer distance in graphite is

Answer 23

340pm

Question 24

Smallest atom in 13th group

Answer 24

Boron

Question 25

Maximum covalency of boron

Answer 25

4

Question 26

The relative stability of +1 oxidation state of group 13 elements increases in the order

Answer 26

Al < Ga < In < TI

Question 27

+1 oxidation states are more ionic than

Answer 27

those in +3 oxidation states

Question 28

Order of electronegativity in grp 13

Answer 28

B > Tl > In > Ga > Al

Question 29

B3+ ion cannot exist in aqueous solution because

Answer 29

- has a small size and a big charge - high sum of first three IEs cannot be compensated by hydration enthalpy

Question 30

Element used in high temp thermometer

Answer 30

Gallium

Question 31

On a weight to weight basis the electrical conductivity of aluminium is twice that of

Answer 31

Cu (copper)

Question 32

Group 14 has

Answer 32

- sp³ hybridised central atom - tetrahedral structure