## 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 M
_{1}V_{1}= M_{2}V_{2}

→ where M_{1} and V_{1} are molarity and volume of a solution, while M_{2} and V_{2} 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 M_{1}V_{1} and M_{2}V_{2} 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

M_{B} = Molar mass of solute

Volume strength of H_{2}O_{2}

- The volume of oxygen liberated by decomposition of one volume H
_{2}O_{2}solution at NTP is called volume strength of H_{2}O_{2}solution - For example “10 volume H
_{2}O_{2}” mean that 1 volume of H_{2}O_{2}solution on decomposition at NTP forms 10 volume of oxygen. ie 1 LH_{2}O_{2}solution decomposes to form 10 L O_{2}at NTP.