nitrogen family type 1

31 Pages·2011·0.56 MB·English

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STUDY PACKAGEThis is TYPE 1 Package
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Subject : CHEMISTRY
Topic : NITROGEN FAMILY
R
Index
1. Key Concepts
2. Exercise I
3. Exercise II
4. Exercise III
5. Exercise IV
6. Answer Key
7. 34 Yrs. Que. from IIT-JEE
8. 10 Yrs. Que. from AIEEE
Student’s Name :______________________
Class :______________________
Roll No. :______________________
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N F Y
ITROGEN AMILY L
I
M
A
Nitrogen(N ) F
N
2 E
G
Occurence: Nitrogen is widely distributed in nature both in free as well as in the combined state. Air isO
R
the most abundant source of free nitrogen. It forms 75% by mass and 78% by volume of the air. In combinedT
I
state, it is found as nitrates such as Chile saltpetre (NaNO ), Indian saltpetre (KNO ) and ammoniumN
3 3 31
comopunds. of
2
e
g
Preparation: Nitrogen can be obtained from the following two sources: Pa
(i) Nitrogen Compounds (ii) Air
(i) Nitrogen from nitrogen compounds: (a) Nitrogen in the laboratory can be obtained by heating L
A
ammonium nitrite or ammonium dichromate. P
O
NH Cl + NaNO → NH NO + NaCl H
m 4 2 4 2 B
s.co NH NO  → A Nmm o+n i2umH nOitrite 81 ,
e 4 2 2 2 8
ss (NH ) Cr O → N + Cr O + 4H O 8
a 4 2 2 7 2 2 3 2 5
clNitrogen is collected by downward dispalcement of water. 0
o 3
k(b) Pure nitrogen can be obtained by passing the ammonia vapours over heated CuO. 89
e 9
w.t 2NH + 3CuO → N + 3Cu + 3H O 0
wwNH3 can also be oxidised to nitrogen 3by Cl2, Br2, a hypo2chlorite, a hyp2obromite or bleaching powder. 0,
0
(c) It can be obtained by the action of nitrous acid (or NaNO and dil. H SO ) on urea. 0
: 2 2 4 0
e NH CONH + 2HNO → 2N + CO + 3H O 0
bsit U2rea 2 2 2 2 2 32
we 5)-
m (d) Pure nitrogen is obtained in small amounts by heating sodium or barium azides in vacuum. 75
Ba(N ) → 3N + Ba 0
fro Barium az3id2e 2 H: (
e P
g )
ka(ii) From air: (a) Commercially nitrogen is obtained by liquefaction of air. The resultant liquid isfractionally Sir
acdistilled in Claude’s apparatus. K.
P R.
dy(b) By removing oxygen of the air with the use of chemical substances. S.
tu Purified air → Hot Cu → Nitrogen A (
S Y
load Purified air → H o t 2 CCauk e+ O2→  C→O 22, CCuOO, N2 KARI
wnCO2 and CO are removed by usual methods. R.
o Purified air → Phosphorus → P O + N G
D 2 5 2 A
H
E U
E S
FR or :
Properties: t
c
(i) It is a colourless, tasteless and odourless gas. It is slightly lighter than air as its vapour density is 14.0. It e
r
Di
is sparingly soluble in water.
S,
(ii) It can be liquefied to a colourless liquid (b. pt. –195.80C). E
S
(iii) It does not help in combustion. Nitrogen itself is non-combustible. S
A
(iv) It is chemically inert under ordinary conditions. However, it shows chemical activity under high L
C
temperatures. O
K
(a) Nitrogen combines with oxygen under the influence of very high temperature like electric spark. E
T
N + O 2NO (Nitric oxide)
2 2
(b) Nitrogen combines with hydrogen in the presence of a catalyst (finely divided iron) at 200 atmospheresY
L
and 400-5000C temperature. MI
N + 3H 2NH (Ammonia) FA
2 2 3 N
(c) Nitrogen combines with metals at red heat to form nitrides. E
G
O
6Li + N 4500C→ 2LiN (Lithium nitride) R
2 3 T
I
N
3Mg + N 4500C→ Mg N (Magnesium nitride) 1
2 3 2 3
of
2Al + N2 8000C→ 2AIN (Aluminium nitride) e 3
g
Non-metals like boron, silicon at bright red heat also combine with nitrogen. Pa
2B + N → 2BN (Boron nitride)
2
3Si + 2N → Si N (Silicon nitride)
2 3 4
(d) Nitrogen combines with calcium carbide to form calcium cyanamide at 10000C. L
A
CaC + N → CaCN + C P
O
2 2 2 H
mThe mixture of calcium cyanamide and carbon is technically known as nitrolinm. B
s.coUses: It is used in the manufacture of NH , HNO , CaCN and other nitrogen compounds. 81 ,
sse 3 3 2 88
a 5
clActive nitrogen: When an electric discharge is allowed to pass through nitrogen under very low pressure 0
o 3
k(about 2 mm), a brialliant luminiscence is observed which persists for sometime after the stoppage of the 89
e 9
w.tdischarge. It is observed that nitrogen after the discharge is more active. This nitrogen is termed active 0
wwnitrogen. 0,
0
The exact nature of active nitrogen is not yet known. 0
: 0
e 0
bsitImportant compounds of Nitrogen 32
we1. Ammonia 5)-
m Nitrogen forms three well known hydrides with hydrogen: 75
0
o (
e fr(imi) pAomrtmanotn oiaf ,t hNeHse3 ,h (yidi)r Hidyeds.razine, NH2·NH2 (N2H4); (iii) Hydrazoic acid, N3H. Ammonia is the most PH:
g )
ka Sir
acOccurence: NH is found in traces in atmopshere. Ammonium salts such as ammonium chloride and K.
Pammonium sulpha3te are found in small amounts in the soil. R.
dy S.
u (
StDiscovery: It was first isolated by Priestly by the action of ammonium chloride and lime. It was named YA
d alkaline air. RI
a A
o K
l
wnPreparation: (i) Ammonium is obtained on a small scale from ammonium salts which evolve it when R.
oheated with caustic soda or lime. G
D A
NH Cl + NaOH → NH + NaCl + H O H
E 4 3 2 U
E(Laboratory Preparation) 2NH Cl + Ca(OH) → 2NH + CaCl + 2H O S
FR 4 (slaked lim2e) 3 2 2 or :
t
(ii) Ammonia is formed when ammonium chloride is heated with litharge. c
e
2NH Cl + PbO → 2NH + PbCl + H O Dir
4 3 2 2
(iii) By reacting nitrides with water, ammonia is obtained. S,
E
AIN + 3H O → Al(OH) + NH S
2 3 3 S
Mg N + 6H O → 3Mg(OH) + 2NH A
3 2 2 2 3 L
(iv) Ammonium can also be formed by doing reduction of nitrates and nitrites with zinc and caustic soda. C
O
Zinc and caustic soda produce nascent hydrogen which reacts with nitrates and nitrites to form ammonia. K
E
NaNO + 8H Zn/NaOH→NaOH + NH + 2H O T
3 3 2
NaNO + 6H Zn/NaOH→NaOH + NH + H O
2 3 2
(v) Calcium cyanamide is also obtained by heating ammonium compounds. Y
L
I
(NH ) SO Heat→ NH + NH HSO M
4 2 4 3 4 4 A
F
Ammonium Ammnoium hydrogen N
sulphate sulphate E
G
NH4H2·PO4 Heat→ NH3 + HPO3 + H2O RO
T
Ammonium Metaphosphoric I
N
dihydrogen phosphate acid 31
(vi) Urea on treatment with caustic soda forms ammonia. 4 of
e
NH CONH + 2NaOH → Na CO + 2NH g
2 2 2 3 3 Pa
urea
Drying of Ammonia gas:
L
The common dehydrating agents like sulphuric acid or CaCl or P O cannot be used as these react with A
2 2 5 P
ammonia. O
H
m 2NH + H SO → (NH ) SO B
es.co CaCl3 + 8N2H 4 → C AamCmlo4·n82iuNmH s4ulphate 881 ,
ss 2 3 2 3 8
a Addition product 5
ocl P O + 6NH + 3H O → 2(NH ) PO 30
k 2 5 3 2 4 3 4 9
e Ammonium phosphate 98
w.tFro drying, quick lime is used as it does not react with ammonia but reacts readily with moisture. 0
ww CaO + H O → Ca(OH) 0,
2 2 0
quick lime 0
e: Manufacture of Ammonia: 00
bsit(i) Haber’s process: The method involves the direct combination of nitrogen and hydrogen according to 32
wethe following reaction: 5)-
m N + 3H 2NH + 24.0 kcal 75
fro Raw materials: Nitrogen and hydro2gen ar2e the chief r3aw materials. Nitrogen is obtained from air by H: (0
e liquefaction followed by fractional evaporation of liquid air. Hydrogen is obtained by electrolysis of water. P
g )
ka Sir
ac(ii) Bosch Process: From Powder gas & water gas K.
P R.
dy S.
u(iii) Cyanamide process: CaCN + 3H O 1800C→ CaCO + 2NH (
t 2 2 3 3 A
S (steam) 3-4 atm Y
d RI
a A
lo(iv) From ammoniacal liquor obtained during coal distillation: Large quantities of ammonia are obtained K
wnas a by-product in the manufacture of coal gas. R.
o G
D A
H
EPhysical properties: (i) Ammonia is a colourless gas with a characterstic pungent odour. it brings tears U
E S
FRinto the eyes. or :
t
(ii) It is highly soluble in water. This high solubility is due to the hydrogen bonding. The solubility of c
e
r
ammonia increases with increase of pressure and decreases with increase of temperature. Di
S,
E
S
S
A
L
C
O
K
E
T
(iii) It can be easily liquefied at room temperature by the application of pressure. Y
L
I
M
(iv) Ammonia molecules link together to form associated molecules through hydrogen bonding. A
F
N
E
G
O
R
T
I
N
1
3
of
5
Higher melting point and boiling point in comparison to other hydrides of V group are due to hydrogen e
g
a
bonding. P
Chemical Properties:(i) Stability : It is highly stable. It decomposes into nitrogen and hydrogen at red
heat or when electric sparks are passed through it. L
A
2NH N + 3H P
3 2 2 O
H
m(ii) Combustion: Ordinary, ammonia is neither combustible nor a supporter of combustion. However, it B
s.coburns in the presence of oxygen to form nitrogen and water. 81 ,
e 4NH + 3O → 2N + 6H O 8
ss 3 2 2 2 8
a 5
cl(iii) Basic nature: Ammonia is a Lewis base, accepting proton to form ammonium ion as it has tendency 0
o 3
kto donate an electron pair. 89
e 9
w.t 0
ww 0,
0
0
: 0
e 0
bsit 32
we 5)-
m It forms salts with acids. 75
NH + HCl → NH Cl (Ammonium chloride) 0
fro 3 Thick4 white fumes H: (
e P
g 2NH + H SO → (NH ) SO (Ammonium sulphate) )
kaIt’s solution is a weak b3ase. 2the 4solution is 4d2escr4ibed as aqueous ammonia. It’s ionisation in water is Sir
acrepresented as: K.
dy P NH3 + H2O → NH4OH NH4+ + OH– S. R.
uThe solution turns red litmus to blue and phenolphthalein pink. (
t A
S Y
d RI
a(iv) Oxidation: It is oxidised to nitrogen when passed over heated CuO or PbO A
o K
wnl 3CuO + 2NH3 → 3Cu + N2 + 3H2O R.
o 3PbO + 2NH → 3Pb + N + 3H O G
D 3 2 2 A
Both chlorine and bromine oxidise ammonia.
H
E U
E 2NH + 3Cl → N + 6HCl S
FR 6NH33 + 6H2C l → 26NH4Cl or :
–––––––––––––––––––––––––––– t
c
e
8NH + 3Cl → N + 6NH Cl r
3 2 2 4 Di
(excess) S,
When chlorine is in excess an explosive substance nitrogen trichloride is formed. E
S
NH + 3Cl → NCl + 3HCl S
3 2 3 A
Iodine flakes when rubbed with liquor ammonia form a dark brown precipitate of ammoniated nitrogen L
C
iodide which explodes readily on drying. O
K
2NH + 3I → NH ·NI + 3HI E
3 2 3 3 T
Hypochlorites and hypobromites oxidise ammonia to nitrogen. Y
L
2NH + 3NaClO → N + 3NaCl + 3 O MI
3 2 2
The oxidation of ammonia with bleaching powder occurs on warming. FA
N
3CaOCl + 2NH → 3CaCl + N + 3H O E
2 3 2 2 2 G
Thus, ammonia acts as a reducing agent. O
R
The restricted oxidation of NH can be done with air, when the mixture is passed over heated platinumT
3 I
gauze at 700-8000C. 1 N
3
4NH + 5O → 4NO + 6H O of
3 2 2 6
This is the Ostwald’s process and used for the manufacture of HNO . e
3 ag
P
(v) Formation of amides: When dry ammonia is passed over heated sodium or potassium, amides are
formed with evolution of hydrogen.
2Na + 2NH → 2NaNH + H
3 2 2 L
A
Sodamide P
O
H
m(vi) Reactions of aqueous ammonia: Many metal hydroxides are formed which may be precipitated or B
s.coremain dissolved in the form oFf ecComl p+l e3xN cHomOpHou nd→ in eFxec(eOsHs o)f +N H3N4OHHC. l 81 ,
asse 3 4 ppt. 3 4 588
cl 0
o 3
k AlCl + 3NH OH → Al(OH) + 3NH Cl 89
e 3 4 3 4 9
w.t ppt. 0
ww CrCl3 + 3NH4OH → Cr(OH)3 + 3NH4Cl 0,
ppt. 00
: CuSO + 2NH OH → Cu(OH) + (NH ) SO 0
bsite 4 4 Blue ppt.2 4 2 4 32 0
we Cu(OH)2 + (NH4)2CO4 + 2NH4OH → [Cu(NH3)4]SO4 + 4H2O 5)-
m Tetramine copper 75
0
o sulphate (
fr (colourless solution) H:
e P
g CdSO + 4NH OH → [Cd(NH ) ]SO + 4H O )
ka 4 4 Cadmium t3et4ramine4 2 Sir
ac sulphate K.
P (Colourless solution) R.
dy AgNO + NH OH → AgOH + NH NO S.
u 3 4 4 3 (
St White ppt. YA
d AgOH + 2NH OH → [Ag(NH ) ](OH) + 2H O RI
a 4 3 2 2 A
o soluble K
l
wnAgCl also dissolve in NH OH solution R.
o 4 AgCl + 2NH OH → [Ag(NH ) ]Cl + 2H O G
D 4 3 2 2 A
E Diamine silver chloride UH
E ZnSO + 2NH OH → Zn(OH) + (NH ) SO S
FR 4 4 ppt. 2 4 2 4 or :
t
Zn(OH) + (NH ) SO + 2NH OH → [Zn(NH ) ]SO + 4H O c
e
2 4 2 4 4 3 4 4 2 r
Tetramine zinc sulphate Di
(soluble) colourless S,
Nickel salt first gives a green precipitate which dissolves in excess of NH OH. E
S
4 S
NiCl + 2NH OH → Ni(OH) + 2NH Cl A
2 4 2 4 L
Ni(OH) + 2NH Cl + 4NH OH → [Ni(NH ) ]Cl + 6H O C
It forms a white precipitate wi2th mercu4ric chloride4. 3 6 2 2 O
K
HgCl + 2NH OH → HgNH Cl + NH Cl + H O E
T
2 4 2 4 2
Amido mercuric
chloride
It forms a grey precipitate with mercurous chloride. Y
L
I
Cl + 2NH OH → Hg+HgNH Cl + NH Cl + H O M
HHHH gggg 2 2 4 (cid:1)(cid:3)(cid:3)(cid:2)(cid:3)(cid:3)2(cid:4) 4 2 FA
Grey N
E
G
O
(vii) Reaction with Nessler’s reagent: A reddish brown ppt. is formed. R
T
2KI + HgCl → HgI + 2KCl I
N
2KI + Hg2I → K2HgI 31
Alkaline solution of K HgI is called Nessler’s rea2gent. 2 4 7 of
2 44 e
This gives brown ppt. with NH called iodide of Million’s base. g
a
3 P
2K HgI + NH + 3KOH → H NHgOHgI + 7KI + 2H O
2 4 3 2 2
Brown ppt.
L
Uses: (i) Liquid hydrogen is not safe to transport in cylinders. Ammonia can be easily liquefied and A
P
transported safely in cylinders. Ammonia can be decomposed into hydrogen and nitrogen by passing over O
H
mheated metallic catalyst. Thus, ammonia is the source for the production of hydrogen at any destination. B
s.co(ii) Ammonia is also used in the manufacture of urea which is an excellent fertilizer of nitrogen. 81 ,
e 8
ss 8
aHydrazine or Diamide NH NH or N H 5
cl 2 2 2 4 0
oThis is another hydride of nitrogen. It is prepared by following methods: 3
k 9
8
e 9
www.t(oif) aR laitstcleh giglu’se .method: A strogn aqueous solution of ammonia is boiled with sodium hypochlorite in presence 0, 0
0
NH + NaOCl → NH Cl + NaOH 0
: 3 2 0
website –––– – – C–N–h–lHo–r–a2–mC–i–ln –+e– – N – –H – – 3 –  – – –→ – – – NH––yHd–r–2a·–zN–in–He––2– +–– –H–C––l––––––– 5)- 32 0
m 2NH + NaOCl → NH NH + NaCl + H O 75
3 2 2 2 0
o (
fr H:
e It burns in air liberating huge amount of energy. The alkyl derivatives of hydrazine are used these days as P
g )
kapotential rocket fuels. It reacts with nitrous acid to give hydrazoic acid, N3H. Sir
ac N2H4 + HNO2 → N3H + 2H2O K.
P R.
dyHydrazine and its salts act as powerful reducing agents. S.
u (
t PtCl + N H → Pt + N + 4HCl A
S 4 2 4 2 Y
d 4AgNO + N H → 4Ag + N + 4HNO RI
a 3 2 4 2 3 A
o 4AuCl + 3N H → 4Au + 3N + 12 HCl K
wnl 3 2 4 2 R.
oIt reduces Fehling’s solution to red cuprous oxide, iodates to iodides and decolourises acidified KMnO G
D 4 A
E solution. It is used as a fuel for rockets, reducing agent and a reagent in organic chemistry. UH
E S
FR or :
t
c
e
Structure r
Di
S,
E
S
S
Hydrazoic Acid, N H A
3 L
C
O
It is the third hydride of nitrogen. It is an acid while other hydrides, NH and N H are bases. It is prepared K
3 2 4 E
by the action of nitrous acid on hydrazine. T
NH ·NH + HNO → N H + 2H O
2 2 2 3 2
It is also formed in the form of sodium salt by passing nitrous oxide on sodamide. Y
L
I
Dry NH3→ N2O→ M
A
F
N
E
G
O
R
T
I
N
It reduces acidified KMnO , nitrous acid, etc. 1
4 2N H + O → 3N + H O of 3
N H + H3 NO → N +2 N O 2+ H O ge 8
3 2 2 2 2 a
It oxidises HCl into Cl P
2
N H + 2HCl → N + NH + Cl
3 2 3 2
Oxides of Nitrogen
L
N O and N O monomeric other are dimeric A
2 3 2 5 P
O
H
mNitrogen forms a number of oxides. The well known oxides of nitrogen are: B
s.co(i) Nitrogen oxide, N2O 81 ,
e(ii) Nitric oxide, NO 8
ss 8
a(iii) Nitrogen trioxide, N O 5
cl 2 3 0
o(iv) Nitrogen dioxide or Di-nitrogen tetroxide, NO or N O 3
k 2 2 9
e(v) Nitrogen pentoxide, N O 98
w.t 2 5 0
ww(I) Nitrogen Oxide, N O or Laughing Gas (Neutral) 0,
2 0
Preparation: 0
: 0
e 0
bsitIt can be prepared by heating ammonium nitrate or a mixture of sodium nitrate and ammonium sulphate. 32
we NH NO →N O + 2H O 5)-
m 2NaNO + 4(NH3 ) SO2 →2NH2 NO + Na SO 75
o 3 4 2 4 4 3 2 4 (0
fr ↓ H:
kage 2N2O + 4H2O Sir) P
ac FeSO + NO →FeSO .NO K.
P 4 Addition4 product R.
udy H SO + 2NH → (NH ) SO (S.
t 2 4 3 4 2 4 A
S Ammonium Sulphate Y
d RI
a A
loThe following reactions can also be used to prepare nitrous oxide. K
own NaNH2 + N2O → NaN3 + NaOH + NH3 G R.
D A
H
E(a) By the action of cold and dilute nitric acid on zinc metal. U
E S
FR Fe/4Zn + 10HNO3 → 4Zn (NO3)2 + N2O + 5H2O or :
t
c
(b) By reducing nitric acid with stannous chloride and hydrochloric acid. e
r
4SnCl + 8HCl + 2HNO →4SnCl + N O + 5H O Di
2 3 4 2 2 S,
E
S
(c) By reducing nitric oxide with sulphur dioxide. S
A
2NO + SO + H O → H SO + N O L
2 2 2 4 2 C
O
K
(d) By heating the mixture of hydroxylamine hydrochloride and sodium nitrite (1 : 1) E
T
NH OH.HCl + NaNO → N O + NaCl + 2H O
2 2 2 2
Properties: Y
L
(a) It is a colourless gas with pleasant odour and sweet taste. MI
(b) When inhaled in moderate quantity, it produces hysterical laughter, hence named as laughing gas. However,FA
N
when inhaled for long, it produces insensibility and may prove fatal too. E
G
(c) It is heavier than air. O
R
(d) It is fairly soluble in cold water but not in hot water. T
I
(e) It is neutral to litmus. 1 N
3
(f) It does not burn but support combustion. The burning material decompose nitrous oxide into nitrogenof
9
and oxygen. The oxygen then helps in the buring. e
g
a
P
2N O 520−900oC→2N + O
2 2 2
It supports combustion of sulphur, phosphorus, magnesium, sodium, candle and a splineter.
L
S + 2N O →SO + 2N A
2 2 2 P
4P + 10N O → 2P O + 10N O
2 2 5 2 H
m Mg + N O → MgO + N B
s.co 2 2 81 ,
e(g) It is decomposed by red hot copper. 8
ss 8
a Cu + N O → CuO + N 5
cl 2 2 0
o 3
k 9
e(h) A mixture of hydrogen and nitrous oxide (equal volumes) explodes with violence. 98
w.t N O + H → N + H O 0
ww 2 2 2 2 0,
0
(i) N O + NaNH → NaH + NH + NaOH 0
: 2 2 3 3 0
e 0
bsitUses: 32
we(i) It is used as the propellant gas for whipped ice-cream. 5)-
m (ii)A mixture of nitrous oxide and oxygen is used as an ananesthetic in dental and other minor surgical 75
0
frooperations. H: (
e P
g )
kaStructure: Sir
acN O is linear and unsymmetrical molecule. It is considered as a resonance hybrid of the following two K.
Pstr2uctures: R.
dy S.
tu :N(cid:5)(cid:5) σ N+ σ O(cid:5)(cid:5): ↔ :N σ N+ σ A (
S π π 2π Y
d RI
a A
loIt has a very small value of dipole moment (0.116D) K
wn R.
o G
DTests: A
H
E(i) It has sweet smell. U
E S
FR((iiii)i) IItt sduopeps onrotst ftohrem co bmrobwusnt ifounm oefs g wloitwh innigtr sicp loinxtiedre.. or :
t
c
(iv) N O does not form H N O with H O nor hyponitrites with alkali. e
2 2 2 2 2 Dir
(II) Nitric oxide, NO Neutral S,
E
S
Preparation: S
A
L
(a) By the action of dilute nitric acid on copper (Lab. Method). the nitric oxide liberated is collected over C
O
water.
K
Ag/Hg/Pb/3Cu + 8HNO → 3Cu(NO ) + 2NO + 4H O TE
3 3 2 2
The liberated gas may contain NO and N O. These are separated by passing the mixture through ferrousY
2 2 L
sulphate solution. NO forms a dark nitroso-ferrous sulphate. When this solution is heated, pure nitric oxideMI
is liberated. FA
N
FeSO + NO → FeSO .NO heate→ FeSO + NO E
4 4 4 G
(impure gas) (Dark Brown) (Pure gas) O
R
T
I
N
(b) A pure sample of nitric oxide is obtained when a mixture of KNO , FeSO and dilute H SO is heated.1
This is also a laboratory method. 3 4 2 4 of 3
0
1
e
g
a
2KNO + H SO → K SO + 2HNO P
3 2 4 2 4 3
2HNO → H O + 2NO + 3O
3 2
[2FeSO + H SO + O → Fe (SO ) + H O] x 3
4 2 4 2 4 3 2
––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– AL
P
2KNO + 6FeSO + 4H SO → K SO + 3Fe (SO ) + 2NO + 4H O O
3 4 2 4 2 4 2 4 3 2 H
m ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––– B
es.con(cit)r iNc iatrciicd o. xide is the first product obtained from the following two processes during the manufacture of 881 ,
ss 8
a 5
ocl(i) Electric arc process: 30
k 9
eBy passing air through an electric arc, nitrogen and oxygen of the air combine together to form nitric oxide. 98
w.t 0
ww N2 + O2 2NO 0,
(ii) Ostwald’s process: 00
e: By restricted oxidation of ammonia with air in presence of platinum gauze catalyst at 7500C, nitric oxide is 00
bsitformed. 32
we 4NH + 5O Pt.gauze→ 4NO + 6H O 5)-
m 3 2 7500C,6atm 2 75
0
o (
frProperties: H:
e (a) It is a colourless gas, slightly heavier than air. P
g )
ka(b) It is sparingly soluble in water. Sir
ac(c) It is paramagnetic indicating the presence of unpaired electron in the molecule. K.
P(d) It is neutral to litmus. R.
dy(e) It at once reacts with oxygen to give brown fumes of nitrogen dioxide. S.
u (
St 2NO + O → 2NO YA
d (f) It is stable oxide. It decomposes into nitrogen a2nd oxygen w2hen heated at 8000C. RI
a A
o K
wnl 2NO 8000C→ N2 + O2 R.
o(g) It is combustible and supports combustion of boiling sulphur and burning phosphorus. G
D A
S + 2NO → SO + N H
E 2 2 U
E(h) It dissolves in cold ferrous sulphate solution by forming a hydrated nitrosyl complex. S
FR [Fe(H2O)6]SO4 + NO → [Fe(H2O)5NO]SO4 + H2O or :
t
Ferrous sulphate Hydrated nitrosyl c
e
complex (Brown colour) Dir
FeSO↓ + HNeaOt + 5H O S,
E
4 2 S
(i) It is oxidised to nitric acid by oxidising agents like acidified KMnO or hypochlorous acid. Thus, it acts S
4 A
as a reducing agent. L
C
6KMnO + 9H SO + 10NO → 3K SO + 6MnSO + 10HNO + 4H O O
4 2 4 2 4 4 3 2 K
[HClO → HCl + O] x 3
E
T
[NO + O → NO ] x 3
2
3HClO + 2NO + H O → 2NO + 3HCl
2 3