## Units of Concentration of a Solution Chemistry Notes

→ The composition of a solution can be expressed in terms of its concentration. Here, the concentration means that amount of solute which is dissolved in certain amount or volume of solution or solvent. The concentration of solution can be expressed in following units :

→ Mass percentage, w/w : The number of parts by mass of solute which is present in 100 g mass parts of solution is called mass percentage of solution. Mass % or % w/W

Example 10 % (w/w) means that 10 g solute is present in 100 g solution. Here, amount of solvent is(100 – 10) = 90g

→ Important Formulae :

• Molar solution = 1 M
• Semi-molar solution = $$\frac{M}{2}$$
• Penti-molar solution = $$\frac{M}{5}$$
• Deci-molar solution = $$\frac{M}{10}$$
• Centi-molar solution = $$\frac{M}{100}$$
• Molarity equation M1 V1 = M2V2

→ where M1 and V1 are molarity and volume of a solution, while M2 and V2 are molarity and volume of other solution.
The molarity of solution obtained by mixing of two solutions of a substance, whose molarity and volume are M1V1 and M2V2 respectively, will be

Relation between Molarity and Normality

• M × Molecular weight of solute = N × Equivalent weight of Solute
• Normality of acid = Basicity × Molarity
• Normality of base = Acidity × Molarity

→ Basicity of acid is equal to the number of substituted H* ions in it and acidity of base is equal to the number of substituted OH ions in it.

Relation between molarity and molality
m = $$\frac{1000 M}{1000-M M_{B}}$$
Where, m = Molality
M = Molarity
d = Density
MB = Molar mass of solute
Volume strength of H2O2

• The volume of oxygen liberated by decomposition of one volume H2O2 solution at NTP is called volume strength of H2O2 solution
• For example “10 volume H2O2” mean that 1 volume of H2O2 solution on decomposition at NTP forms 10 volume of oxygen. ie 1 LH2O2 solution decomposes to form 10 L O2 at NTP.