P BLOCK (2) 15 and 16

Question 1

Molecular nitrogen comprises

Answer 1

78% of atmospheric volume

Question 2

sodium nitrate,

Answer 2

Chile saltpetre

Question 3

potassium nitrate

Answer 3

Indian salt petre

Question 4

Phosphorous occurs in

Answer 4

Ca9(PO4)6. CaX2
(X = F, Cl or OH)

Question 5

arsenic, antimony, and bismuth are mainly found in

Answer 5

sulfide ores

Question 6

trend in radius in the 15th group

Answer 6

A considerable increase from N to P. only a small increase from As to Bi

Question 7

the trend in IE in the 15th group

Answer 7

decreases down the group

Question 8

trend in EN in the 15th group

Answer 8

Decreases down the group. but for heavier elements, the difference is not that prominent

Question 9

Boiling point?in 15th group

Answer 9

increases down the group

Question 10

melting point in the 15th group?

Answer 10

increases till As then decreases to Bi

Question 11

Bismuth hardly forms elements in which OS

Answer 11

-3

Question 12

The only well-characterized Bi (V) compound is

Answer 12

BiF5

Question 13

Oxidation states of Nitrogen that disproportionate in acid medium

Answer 13

+1 to +4

Question 14

phosphorous OS that disproportionate in both acidic and alkaline medium

Answer 14

+5 to -3

Question 15

anomalous property of N is due to

Answer 15

small size, high electronegativity, high ionization enthalpy, and non-availability of orbitals

Question 16

why the heavier elements cannot form p pi p pi bonding

Answer 16

their atomic orbitals are so
large and diffuse that they cannot have effective overlapping

Question 17

why is a single N–N bond weaker than a single P–P bond

Answer 17

because of the high interelectronic repulsion of the non-bonding electrons, owing to the small bond length

Question 18

order of stability of hydrides of group 15

Answer 18

The stability of hydrides decreases from NH3 to BiH3

Question 19

reducing character of hydrides of group 15

Answer 19

increases

Question 20

why does ammonia have higher MP and BP?

Answer 20

because it forms hydrogen bonding

Question 21

acidic character of oxides of group 15

Answer 21

decreases down the group

Question 22

The oxides of the type E2O3 of nitrogen and phosphorus are

Answer 22

purely acidic

Question 23

oxides of E2O3 arsenic and antimony

Answer 23

amphoteric

Question 24

oxides of E2O3 bismuth

Answer 24

predominantly basic.

Question 25

in the case of Nitrogen, which trihalide is stable

Answer 25

only NF3

Question 26

which trihalide is ionic in the case of group 15

Answer 26

BiF5

Question 27

group 15 elements react with metals in which OS

Answer 27

+3

Question 28

% of oxygen in earth's crust

Answer 28

46.6%

Question 29

% of oxygen in the air

Answer 29

21%

Question 30

% of sulfur in the earth's crust

Answer 30

0.03 - 0.1%

Question 31

group 16, the trend in atomic and ionic radii

Answer 31

increases down the group

Question 32

trend in ionization enthalpy of group 16

Answer 32

IE decreases down the group

Question 33

electron gain enthalpy order of group 16

Answer 33

OSe>Te>Po

Question 34

EN of group 16

Answer 34

decreases down the group

Question 35

allotropy is exhibited by which all elements in group 16

Answer 35

all elements exhibit allotropy

Question 36

order of MP and BP

Answer 36

increases down the group

Question 37

The large difference between the melting and boiling points of oxygen and sulfur may be explained based on?

Answer 37

their atomicity; oxygen exists as a diatomic molecule (O2) whereas sulfur exists as a polyatomic molecule (S8).

Question 38

The stability of -2 oxidation state in group 16

Answer 38

decreases down the group

Question 39

oxidation states exhibited by elements of group 16

Answer 39

+2, +4, +6

Question 40

Bonding in +4 and +6 is

Answer 40

covalent

Question 41

the effect of the absence of d orbitals in oxygen

Answer 41

limits its covalency to four and in practice, rarely exceeds two

Question 42

acidic character of hydrides of group 16

Answer 42

increases down the group

Question 43

the thermal stability of hydrides

Answer 43

decreases down the group

Question 44

selenium dioxide is a

Answer 44

solid

Question 45

the hydride without reducing property

Answer 45

water

Question 46

reducing property of oxides of group 16

Answer 46

decreases down the group

Question 47

SO2 is a ______ agent while TeO2 is a _________ agent

Answer 47

reducing agent and oxidizing agent

Question 48

both types of oxides in Group 16 are

Answer 48

acidic

Question 49

among hexahalides which one is only stable?

Answer 49

hexafluoride

Question 50

which hexa fluoride is exceptionally more stable?

Answer 50

SF6

Question 51

which all elements of group 16 form dichlorides and dibromides

Answer 51

all elements in group 16 except Oxygen

Question 52

mono halides of group 16 exist as

Answer 52

dimers