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Nitric acid properties- Part 1

Nitric acid

source : sciencewith pizzi.weebly.com

Chemical properties :

1) Acidic nature:

It is strong monobasic acid. It reacts with alkali, metal carbonate and metal bicarbonate to form salt.

HNO3 + NaOH  ———> NaNO3 + H2O

2HNO3 + Na2CO3 ——-> 2NaNO3 + H2O + CO2

HNO3 + NaHCO3 ——-> NaNO3 + H2O + CO2

 

2) Oxidizing properties of Nitric acid :

A) Oxidation of non metals : 

a) Reaction with Carbon:

2HNO3  ——> H2O + 2NO2 + [O]   ] x 2

C  + 2[O] ——-> CO2

Equation as a whole,

4HNO3 + C ——> 2H2O+ CO2 + 4NO

b) Reaction with sulphur:

6HNO3  ——> 3H2O + 6NO2 + 3[O]

S + 3[O] + H2O ——-> H2SO4

Equation as a whole,

6HNO3 + S  —-> 2H2O + H2SO4 + 6NO2

c) Reaction with Phosphorus :

2HNO3  ——-> H2O + 2NO2 + O ] x 5

2P + 5[O]  + 3H2O —-> 2H3PO4

Equation as a whole,

10HNO3 +2P —-> 10  NO2  + 2H3PO4 + 2H2O

d) Reaction with I2:

2HNO3 ——> H2O+ 2NO2 + O ]x5

10HNO3 ——-> 5H2O + 10 NO2 + 5 [O]

I2 + 5 [O] +H2O ———>2HIO3

Equation as a whole,

10HNO3 + I2 —-> 10 NO2 + 2HIO3+ 4H2O

B) Oxidation of metalloids:

a)  With hot and concentrated HNO3, Arsenic is oxidized into arsenic acid:

2HNO3 ——> H2O + 2NO2 + O ]x5

2As + 5 [O] + 3H2O —-> 2H3AsO4

Equation as a whole,

10 HNO3 + 2As  ——-> 2H2O + 10 NO2 + 2H3AsO4

b)  Antimony is oxidized into antimonic acid:

10HNO3 ——> 5H2O + 10 NO2 + 5 [O]

2Sb + 5[O] + 3H2O —–>2H3SbO4

Equation as a whole,

10 HNO3 + 2Sb ——> 2H3SbO4 + 10NO2 + 2H2O

ii) Pb + HNO3 (concentrated) ——> Pb(NO3)2 + NO2 + H2O

C) Oxidation of reducing agent :

a) H2S is oxidized to S:

2HNO3 —–> H2O+ 2NO2 + O

H2S +O —–> H2O + S

Equation as a whole,

2HNO3 + H2S —–> 2H2O + S + 2NO2

b) SO2 is oxidizes into H2SO4 :

SO2 + O + H2O ——> H2SO4

2HNO3 —–> H2O + 2NO2 + O

Equation as a whole,

SO2 + 2HNO3 —–> H2SO4 + 2NO2

c) KI is oxidized into I2:

2HNO3 —–> H2O + 2NO + 3[O]

2KI +2 HNO3 + [O] —–> 2KNO3 + I2 +H2O ] x 3

6KI +6HNO3 + 3[O] —–> 6KNO3 +3I2 +3H2O

Equation as a whole,

8HNO3 + 6KI  ——> 4H2O + 6KNO3 + 3I2 + 2NO

d) In presence of H2SO,  ferrous sulphate is oxidized to ferric sulphate:

2HNO3 —–> H2O + 2NO + 3[O]

2FeSO4 +H2SO4 + O —> Fe(SO4)2 +H2O ] x3

Equation as a whole,

2HNO3 + 6 FeSO4 + 3H2SO4 —-> 4H2O + 2NO + 3Fe2(SO4)3

FeSO4 + NO —–> FeSO4. NO [Nitroso ferrous  sulphate(Brown complex)]

 

 

Saroj Bhatia: Dr. Saroj Bhatia is an Ph.D in chemistry who has been teaching chemistry for over a decade. Currently she is a respected principal of a renowned college in her hometown. She took this medium for online users. Her proudest achievement is helping people learn chemistry.
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