Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

VOLUMETRIC ANALYSIS
Grade XII
Volumetric analysis
Volumetric analysis is defined as the process of the
determination of concentration of unknown solution by
finding its volume which will exactly react with a definite
volume of another solution of known concentration
...
of parts by wt
...
008 parts by wt
...
of oxygen or 35
...
of
chlorine
...

of a substance, i
...
one can have more than one
equivalent weights depending on chemical change
...
of different substances are calculated as
follows:
𝐀𝐭𝐨𝐦𝐢𝐜 𝐰𝐞𝐢𝐠𝐡𝐭

a) Equivalent wt
...


Valency

Equivalent
wt
...
5

1

35
...
of radical (ion) =

𝒘𝒕
...
𝒐𝒇 𝒄𝒉𝒂𝒓𝒈𝒆 𝒐𝒏 𝒊𝒕

element

Mass of
radical
...
of
charge on
radical

Equivalent
wt
...
5

1

35
...
of acid =

𝐛𝐚𝐬𝐢𝐜𝐢𝐭𝐲

element

Mol
...


Basicity

Equivalent
wt
...
5

1

36
...
67

CH3COOH

60

1

60

𝐦𝐨𝐥
...
of base =

𝐚𝐜𝐢𝐝𝐢𝐭𝐲

Base

Mol
...


Acidity

Eq
...


NaOH

40

1

40

KOH

56

1

56

Ca(OH)2

74

2

37

Al(OH)3

78

3

26

e) Equivalent wt
...
𝐩𝐞𝐫 𝐦𝐨𝐥𝐞𝐜𝐮𝐥𝐞
𝐦𝐨𝐥𝐞𝐜𝐮𝐥𝐚𝐫 𝐰𝐞𝐢𝐠𝐡𝐭

𝐭𝐨𝐭𝐚𝐥 𝐜𝐡𝐚𝐧𝐠𝐞 𝐢𝐧 𝐨𝐱𝐢𝐝𝐚𝐭𝐢𝐨𝐧 𝐧𝐨
...
wt
...
wt
...
6

K2Cr2O7

294

6

49

(COOH)2

90

2

45

H2S

34

2

17

Equivalent wt
...
= 7-2 =5
Eq
...
of KMnO4 in acidic medium= 158/5 =31
...
= 7-4 =3
Eq
...
of KMnO4 in neutral medium= 158/ 3= 52
...
= 7-6 =1
Eq
...
of KMnO4 in alkaline medium= 158/1 =158

Concentration of solution
The amount of substance (solute) present in a definite
quantity of the solution is called concentration
...

𝑤𝑡
...
/vol
...
solution
...
/wt
...
solution
...
/vol
...
present in 100 ml
...

c) Normality (N): It is defined as the no
...

Normality(N) =

𝑛𝑜
...
𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑖𝑛 𝑙𝑖𝑡𝑟𝑒

i) Normal solution: The solution containing 1 g
...

Solute in 1 liter solution is called normal solution
...
eqvt
...

iii) Deci-normal solution: The solution containing 0
...
eqvt
...

iv) Centi-normal solution: The solution containing
0
...
eqvt
...

d) Molarity (M): It is defined as the no
...

Molarity (M) =

𝑛𝑜
...
𝑜𝑓 𝑠𝑜𝑙𝑢𝑡𝑖𝑜𝑛 𝑖𝑛 𝑙𝑖𝑡𝑟𝑒

Molar solution: The solution containing 1 mole solute
in one liter solution is molar solution
...
of moles of
solute dissolved per kg
...

𝑛𝑜
...


f) Formality (F): It is defined as the no
...
formula wt
...
It is used in
ionic compound
...
So, it is not in common practice
nowadays
...
of moles of
solute or solvent and total moles in solution
...
of moles of solute = n1
the no of moles of solvent = n2
total no
...
) solution contains 50 g
...
corresponding solution contains 5 g
...

By definition, g L-1 =50 & %( w/v) = 5
𝑔 𝑝𝑒𝑟 𝑙𝑖𝑡𝑒𝑟

So, %( w/v) =

%( w/w) =

10
𝑔
...
𝑔𝑟𝑎𝑣𝑖𝑡𝑦

Relation between normality and g L-1
no
...
eqvt
...
of solution in litre
wt
...


=

eqvt
...
of solute

=

x

vol
...
of solute in g
...
wt
...
wt
...


g L-1 = Normality x eqvt
...


Relation between molarity and g L-1
Molarity =
=

no
...
of solution in litre
wt
...


mol
...
of solute

=

x

1

vol
...
of solute in g
...
of solution in litre

x

1
mol
...
of solute

= gL-1 / mol
...

∴g L-1 = Molarity x mol
...


Relation between Normality &
Molarity
We have, g
...
L-1 Or, Normality x eqvt
...
=
Molarity x mol
...

Or, Normality =

𝑚𝑜𝑙
...


x Molarity

∴N =z x M, where z = valence factor

Summary
1
...
Wt
...
g L-1 = Molarity x mol
...

3
...
𝑝𝑒𝑟 𝑙𝑖𝑡𝑟𝑒

4
...
𝑝𝑒𝑟 𝑙𝑖𝑡𝑟𝑒
10 𝑋𝑠𝑝
...
Normality =
6
...
𝑋 10
𝑒𝑞
...


=

=

𝑒𝑞
...
𝑋 10
𝑚𝑜𝑙
...
N = z M (z =valence factor)
For preparation of solutions
8
...
w =

𝑁𝐸𝑉
1000

where, w= wt
...
; N = normality of solution; E = eqvt
...
of solute; V = vol
...


𝑀𝑀𝑜𝑙
...
of solute in g
...
wt
...
of solution in ml
...
It should be readily available in almost pure form
(99
...

II
...


III
...
It should have fairly high equivalent and molecular
weight to minimize the weighing error
...
2H2O, KMnO4, Na2CO3 etc
...
Standard solution are of two types

---