Group 14

Question 1

Order of IE1:

Answer 1

C>Si>Ge>Pb>Sn

Question 2

Order of IE2:

Answer 2

C>Si>Ge>Pb>Sn

Question 3

Density order

Answer 3

Pb>Sn>Ge>C(diamond)>Si>C(graphite)

Question 4

Mpt:

Answer 4

C>Si>Ge>Pb>Sn

Question 5

Bpt:

Answer 5

Si>Ge>Sn>Pb

Question 6

Most stable allotrope of carbon

Answer 6

Graphite

Question 7

Product of Graphite+ alkaline permanganate:

Answer 7

Mellitic acid + Oxhalic Axid
C6(COOH)6

Question 8

diamond is a good conductor of ?

Answer 8

heat, not electricity

Question 9

graphite is a good conductor of____.State reasons.

Answer 9

Electricity, not heat.
Due to weak vanderwaal’s force between the layers.
Good at conducting e due to pi electrons.

Question 10

TIN:Types

Answer 10

alpha-tin: white
beta tin: grey (like diamond)

Question 11

alpha and beta tin are in eqbr at T*

Answer 11

132 deg Celsius

Question 12

No of five membered and six membered rings in fullerenes:

Answer 12

12, n/2 - 10
n= no.of C atoms.

Question 13

Kernite

Answer 13

Na2B4O7.4H2O

Question 14

coordination number and mass are ____related:.

Answer 14

Directly

Question 15

MCl3 on hydrolysis in water forms- write shape,hybr of M

Answer 15

[M(OH)]4- , thd, sp3

Question 16

AlCl3 in acidic solution forms

Answer 16

[Al(H2O)6]3-, sp3d2

Question 17

Al+NaOH+H2O—>

Answer 17

2Na[Al(OH)4-+3H2

Question 18

Al+ HNo3—>

Answer 18

rendered passive due to protective oxide layer.

Question 19

ONly metal in p block unreactive with halogens

Answer 19

Thallium

Question 20

Heating borax

Answer 20

1.) Swells up
Borax—>Na metaborate(Na2B4O7)
2) Transparent liq—>Borax bead
Na2B4O7—->NaBo2(metaborate)+B2O3(B anhydride)

Question 21

Orthoboric acid

Answer 21

H3BO3
1) white, crystalline,soapy
2) sparingly sol. in water, highly soluble in hot water.
3) Formed by adding water and Hcl to borax,
hydrolysis of boron compounds
4) weak monobasic acid

Question 22

Diborane formation

Answer 22

BF3+LiAlH4–>B2H6+LiF+3AlF3

NaBH4+I2–>B2H6+2NaI+H2

BF3+NaH–>B2H6+Naf
temp=450k

Question 23

diborane

Answer 23

colourless
highly toxic,
flammable spontaneously in air.
bpt=180k

B2H6+ O2–>B2O3+H20
rxn with lewis base:
forms borane adduct.

Question 24

REdn of Diborane with AMmonia

Answer 24

B2H6.2NH3,-heat–>inorganic benz B3N3H6

Question 25

commonality btwn LiAlH4 and NaBH4:

Answer 25

used as reducing agents in organic synthesis

Question 26

Boron

Answer 26

extremely hard refractory solid

high mpt,low density, very low electrical conductivity

Question 27

orthoboric acid soln

Answer 27

used as mild antiseptic

Question 28

14: Halide+water—>

Answer 28

Complex by accepting e- pairs(SiF62-, [GeCl6]2- , Sn(OH)6]2-)

Question 29

14: Reactivity tow Halogens

Answer 29

MX2, MX4—>Products,which are covalent,
Exception: SnF4, PbF4—>ionic
PbI4 does not exist because enough energy is not released to excite 6s2 e-s

Question 30

the central atom(C) cannot accommodate the lone pair of electrons from
oxygen atom of water molecule in d orbital. Infer.

Answer 30

CCl4 cannot hydrolyze

Question 31

CO

Answer 31

colourless,odorless,almost water insoluble gas
powerful reducing agent
oxidizes all metal exides except those of alkaline earth, Al and few transition elements.

Question 32

Silicones

Answer 32

They have in general high thermal stability,
high dielectric strength and resistance to
oxidation and chemicals.