p block(c fam)

Question 1

caarbon family

Answer 1

carbon
silicon
germinium
tin
lead
flerovium

Question 2

elemental forms of carbon

Answer 2

graphite,diamond,coal

Question 3

combined state of carbon

Answer 3

metal carbonates,hydrocarbons,CO2 in air

Question 4

silicon present in nature as

Answer 4

silica and silicates

Question 5

tin occur as

Answer 5

cassiterite

Question 6

lead occur as

Answer 6

galena

Question 7

who seen in tracce amout

Answer 7

germinium

Question 8

valence shell Ec

Answer 8

ns2np2

Question 9

increment of covalent radius

Answer 9

considerable increase from c to si ,si to pb small increase

Question 10

reason for small increment in size from si to lead

Answer 10

due to presence of completely filled d and f orbitals in heavier atoms

Question 11

IE

Answer 11

first IE is grreater than group 13.
generally decreases down the group

Question 12

EN

Answer 12

more EN than grp 13.EN values from si to pb are almost same

Question 13

physical propertiess

Answer 13

all are solids.
C and Si - non metals.
Ge - metalloid
Pb - soft metal

Question 14

grp 14 elements have 4 electrons in outermost shell.common oxidation state?

Answer 14

+4 and +2

Question 15

did carbon exhibits negative oxn state

Answer 15

yes

Question 16

compounds in +4 oxn state generally covalent in nature .why

Answer 16

since the value of sum of first 3 IE are high

Question 17

in heavier members the tendancy to shoe +2 state …

Answer 17

increases

Question 18

most positive electron gain enthalpy (high)

Answer 18

Neon

Question 19

all members when heated with oxygen forms oxides,in the form of

Answer 19

monoxide and dioxide

Question 20

do they react with water

Answer 20

C,Si,Ge are unaffected by water.
Sn decompposes steam to form dioxide and dehydrogen.
Pb is unaffected

Question 21

why pd is unafffected by water

Answer 21

it forms a protective oxide film

Question 22

these elements can form halides of the formula

Answer 22

MX2 and MX4

Question 23

do C react with halogen

Answer 23

no

Question 24

sitric acid

Answer 24

Si(OH)4

Question 25

anomolous behaviour of C

Answer 25

small in size,high EN,high IE,unavailability of d orbital

Question 26

why covalency of C is limitted to 4 and others can expand their covalency

Answer 26

cos s and p orbitals of C is taking part in bonding..hence it can accomodate only 4 pair of electrons..others have d orbital and they can expand their covalency

Question 27

catenation?

Answer 27

carbon have the tendancy to link with one another through covalent bonds to form chains and rings

Question 28

how catenation possible in C?

Answer 28

it has the ability to form ppi-ppi bond small size high EN

Question 29

allotropes of Carbon

Answer 29

diamond,graphite,fullerene

Question 30

order of IE

Answer 30

C>Si>Ge>Pb>Sn

Question 31

hybridisation of diamond

Answer 31

sp3

Question 32

enthalpy of formation of diamond

Answer 32

1.90KJ/mol

Question 33

in diamond a carbon linked to four carbon in ........ faashion

Answer 33

tetrahedral

Question 34

c-c bond length in diamond

Answer 34

154pm

Question 35

in this structure ........... covalent bonds are present

Answer 35

directional

Question 36

hardest substance on the earth

Answer 36

diamond

Question 37

it is used as an abrasive sharpening hard tools.which?

Answer 37

diamond

Question 38

1 carat diamond

Answer 38

200mg

Question 39

hybridisation of graphite

Answer 39

sp2

Question 40

enthalpy of formation of graphite

Answer 40

0

Question 41

in graphote layers are held by ....... force

Answer 41

van der waals force

Question 42

distance btw 2 layers

Answer 42

340pm

Question 43

each layer is composed of ............. rings of carbon atom

Answer 43

planar hexogonal rings

Question 44

c-c bond length within in the layer

Answer 44

141.5pm

Question 45

types of bonds btw carbon atom in hexagonal ring

Answer 45

3 sigma bonds btw 3 carbon atom.4th electrons forms pi bond

Question 46

why graphites conduct electricity?

Answer 46

electrons are mobile over the whole sheet

Question 47

graphite is used as a dry lubricant in machines running at high temperature,where oil cant be used .why?

Answer 47

graphites cleave easily btw the layers and therfore it is very soft and slippery

Question 48

which is the most pure form of carbon.and its hybridisationn?

Answer 48

fullerene,sp2

Question 49

how fulllerenes are prepared?

Answer 49

by heating graphite in an electric arc in the presence helium or argon..then condeses out C60 with C70 and other fullerenes

Question 50

C60 named as

Answer 50

Buckminster fullerence

Question 51

general name ........ refers to the family of spheroidal carbon cage molecules

Answer 51

fullerence

Question 52

shape of C60

Answer 52

soccer ball

Question 53

C60 contains

Answer 53

12 five membered ring 20 six membered rings six membered rrings are fused to 5 membered rings and other 6 membered rings but 5 membered rings are only fused to 6 membered rings

Question 54

both c-c single bond and double bond are present in this structure

Answer 54

yes

Question 55

which are the impure amorphous forms of graphites or fullerenes

Answer 55

carbon black,coke,charcoal

Question 56

....... is formed by burning hydrocarbon in limited air supply

Answer 56

carbon black

Question 57

charcoal and coke are obtained by

Answer 57

heating wood and ccoal respectively in absence of air

Question 58

why graphite is used for electrodes in batteries and industrial electrolysis.why?

Answer 58

graphite is a good conductor

Question 59

...... made from graphite are inert to dil. acids and allkalies

Answer 59

crucibles

Question 60

being highly porous,activated charcoal is used in

Answer 60

adsorbing poisonous gas