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Title: Non-metals Details Questions and Answers
Description: Elements are divided into two main classes: Metals and non-metals. This division is based upon differences in the characteristic properties of the two types of elements. Metals, in general, are solids (except mercury which is a liquid) having a bright appearance (metallic lustre) and are good conductors of heat and electricity. They are malleable (i.e. they can be flattened into thin sheets by hammering) and ductile (i.e. they can be drawn out into wire by stretching). On the other hand, some non-metals are gases, while others are solids (except bromine which is a liquid) which do not posses metallic lustre (except iodine). They are not malleable or ductile.
Description: Elements are divided into two main classes: Metals and non-metals. This division is based upon differences in the characteristic properties of the two types of elements. Metals, in general, are solids (except mercury which is a liquid) having a bright appearance (metallic lustre) and are good conductors of heat and electricity. They are malleable (i.e. they can be flattened into thin sheets by hammering) and ductile (i.e. they can be drawn out into wire by stretching). On the other hand, some non-metals are gases, while others are solids (except bromine which is a liquid) which do not posses metallic lustre (except iodine). They are not malleable or ductile.
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Chemistry
Non-metals
1
...
Nitric acid, (iii)
chlorine, (iv) hydrogen on non – metals
...
(i) Reaction with oxygen: Non – metals like carbon and sulphur combine with oxygen
to form CO2 and SO2 respectively
...
C + O2
CO2 (g) + H2O
CO2 (g)
H2CO3
( Carbonic acid )
S + O2
SO2 (g)
SO2 (g) + H2O
H2SO3
(sulphurous acid)
(ii) Reaction with nitric acid: Sulphur reacts with concentrated nirtric acid to form
H2SO4 and NO2
...
P4 + 6Cl2
(iv)
4 PCl3 (g)
H2 + Cl2
2 HCl (g)
Reaction with hydrogen:
Nitrogen reacts with hydrogen to give Ammonia
...
What happens when silicon is treated with (i) oxygen, (ii) chlorine, (iii) steam,
(iv) hydrochloric acid (v) sodium hydroxide
...
Si + O2
SiO2
Silicon dioxide
(ii) Reaction with chlorine: On heating to a temperature of 450C, silicon combines
with chlorine to from silicon tetra chloride
...
Si
+
silicon
(Red hot)
2H2 O
Heat
steam
SiO2
2H2
+
Silicon
dioxide
hydrogen
(iv) Reaction with Hydrochloric Acid: Silicon reacts with hydrochloric acid to form
silicon tetra chloride and hydrogen gas is liberated
...
Si
+
2NaOH + H2O
Na2SiO3
sodium silicate
+
2H2
hydrogen
3
...
(i) Reaction with chlorine: White phosphorus spontaneously catches fire in chlorine
forming phosphorus trichloride and pentachloride while the red phosphorus catches fire
in chlorine only on heating
...
P4 + 3 NaOH + 3H2O
PH3 +
Phosphine
3 NaH2 PO2
sodium
hypophosphite
(iii) Reaction with acids: When white phosphorus is heated with concentrated nitric
acid, it is oxidized to orthophosphoric acid H3PO4
...
H3PO4 + 5NO2
Orthophosphoric Acid
+ H2O
Explain with equations what happens when (i) sulphur is heated with carbon, (ii)
hydrogen gas is passed through boiling sulphur, (iii) sulphur is treated with hot
concentrated sulphuric acid, (iv) sulphur is heated with concentrated nitric acid
...
C
+
2S
CS2
carbon sulphur
carbon disulphide
(ii) When hydrogen gas is passed through boiling sulphur, a foul smelling gas
hydrogen sulphide is formed
...
S +
2 H2SO4
sulphur
sulphuric acid
(hot and cone)
3 SO2
sulphur dioxide
+
2H2O
water
(iv) Reaction with nitric acid; Sulphur is oxidised to sulphuric acid by hot and
concentrated nitric acid
...
6HNO3
nitric acid
(hot and cone)
H2SO4
sulphuric
acid
+
6NO2
nitrogen
dioxide
+ 2H2O
Explain the chemical properties of non – metals
...
Non metals combine with oxygen to form oxides
...
2
...
For example sulphur reacts with concentrated HNO3 to
form sulphuric acid
...
H2SO4 + 6 NO2 (g) + 2H2O
They react with chloride to form chlorides
...
P4 + 6Cl2
4
...
H2 + S
H2 S
N2 + 3H2
6
...
(a) Reaction with oxygen: Silicon burns in the oxygen of air to form a white solid
compound called silicon – dioxide (silica / sand)
...
Si + 2Cl2
Heat
450C
SiCl4
Silicon tetra chloride
(c) Reaction with steam: Red hot silicon reacts with steam to form silicon dioxide and
hydrogen gas
...
Si
+
4HCl
SiCl4
2H2
+
silicon
tetrachloride
hydrogen
(e) Reaction with sodium hydroxide: Silicon reacts with hot sodium hydroxide
solution to form sodium silicate with the evolution of hydrogen gas
...
+
2H2
hydrogen
What is allotropy? Explain the different allotrophic forms of phosphorus
...
The various allotropic modification of phosphorus are:
1
...
Red phosphorus
3
...
Metallic black phosphorus
5
...
8
...
State and colour
White solid when freshly cut
changes to yellow on keeping
...
2
...
Odourless
...
Hardness
Soft, can be cut with a knife
...
4
...
8 g/cm3 (lighter)
2
...
Ignition
temperature
30 C (low)
260 C (high)
6
...
Solubility
Soluble in carbon – disulphide
...
8
...
Chemical
reactivity
Very reactive
Less reactive
10
...
Stable in air, does not
show phosphorescence
...
Action of chlorine Combines spontaneously with
chlorine to give PCl3 and PCl5
...
12
...
Phosphine gas is evolved
...
Phosphorite
(or Rock – Phosphate)
2
...
Apatite
– Ca3 (PO4)2
– 3 Ca3 (PO4)2
...
CaF2
Extraction of phosphorus:
Modern electro thermal process: In this process phosphorous is extracted by heating
bone ash or phosphate rock, phosphorite, [ Ca3(PO4)2 ] , with sand (SiO2) and coke in an
electric furnace at about 1500 C
...
The electric arc is set up
between the electrodes E
...
(i) Silica reacts with calcium phosphate to give phosphorus pentoxide is formed
...
Impure phosphorus obtained flows into the collector as shown
...
Charge
Hooper
Phosphorus
Vapour
Worm
Conveyor
Calcium
Phosphate +
Sand and coke
–
+
Carbon arc
Slag
(S)
Extraction of Phosphorus
The impure solid phosphorus is purified by melting under a solution of chromic
acid and allowed to remain there for few hours
...
Phosphorus is then cast into sticks by means of tube of glass or tin standing in cold water
...
9
...
(a) Exposed to excess air: Phosphorus burns in air forming phosphorus trioxide and
phosphorus pentoxide
...
P4 + 6Cl2
4 PCl3
Phosphorus trichloride
P4 + 10Cl2
4 PCl5
Phosphorus pentachloride
(c) Heated with concentrated nitric acid: When white phosphorus is heated with
concentrated nitric acid, it is oxidized to orthophosphoric acid H3PO4
...
P4 + 3 NaOH + 3H2O
PH3
phosphine
+
3 NaH2 PO2
sodium
hypophosphite
10
...
Water is heated to 180C under pressure is forced
through the outermost pipe
...
The hot water melts the sulphur and a foam of water, sulphur and air is produced
...
The
molten sulphur is run into separating tanks where it is separated from air and water
...
5% pure
...
Discuss the various allotropes of sulphur in detail
...
They are
(a) Rhombic sulphur, (b) Monoclinic or Prismatic sulphur and (c) Plastic sulphur or
Amorphous sulphur
...
(a) Rhombic sulphur: This is obtained by dissolving
the extracted roll sulphur in carbon disulphide and slowly
allowed to evaporate in air slowly
...
It is a pale yellow crystalline
solid
...
It is stable below 96C
...
(b) Monoclinic sulphur: It is prepared by melting rhombic sulphur in a dish
and allowing it to cool until a crust is formed at the surface
...
The liquid sulphur lying below the crust (which has not yet solidified) is
poured out
through one of the holes
...
It melts at 120 C
...
(c) Plastic sulphur: It is prepared by boiling molten sulphur up to 445C
...
It is plastic like in texture
...
Title: Non-metals Details Questions and Answers
Description: Elements are divided into two main classes: Metals and non-metals. This division is based upon differences in the characteristic properties of the two types of elements. Metals, in general, are solids (except mercury which is a liquid) having a bright appearance (metallic lustre) and are good conductors of heat and electricity. They are malleable (i.e. they can be flattened into thin sheets by hammering) and ductile (i.e. they can be drawn out into wire by stretching). On the other hand, some non-metals are gases, while others are solids (except bromine which is a liquid) which do not posses metallic lustre (except iodine). They are not malleable or ductile.
Description: Elements are divided into two main classes: Metals and non-metals. This division is based upon differences in the characteristic properties of the two types of elements. Metals, in general, are solids (except mercury which is a liquid) having a bright appearance (metallic lustre) and are good conductors of heat and electricity. They are malleable (i.e. they can be flattened into thin sheets by hammering) and ductile (i.e. they can be drawn out into wire by stretching). On the other hand, some non-metals are gases, while others are solids (except bromine which is a liquid) which do not posses metallic lustre (except iodine). They are not malleable or ductile.