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## Concentration of Solution

Amount of constituents (solute) present in a solution is called concentration. Concentration is used to describe the composition of a solution quantitatively. Concentration is described in the following ways:

### (i) Mass percentage (w/w):

Mass % of component =

### (ii) Volume percentage (%) (v/v):

Volume percentage (%) of component =

### (iii) Mass by volume percentage (%) (w/v)

Mass of solute dissolved in 100ml of solution.

Mass of by volume percentage (%) to describe concentration is used generally in medicine and pharmacy.

### (iv) Parts per million (ppm):

Parts per million =

Parts per million is used to describe the concentration when solute is present in trace (very small) quantities.

### (v) Mole fraction:

Mole fraction of component (x) =

Let in a binary mixture, the number of moles of A and B are respectively

Therefore,

Mole fraction of a solution having i number of components

It is found that sum of all the mole fractions in a given solution is equal to unity (1).

### (vi) Molarity:

Number of moles of solute per liter of solution is called molarity. It is generally denoted by “ M ”.

### (vii) Molality:

Number of moles of solute per kg of solvent is called Molality. It is generally denoted by letter “ m ”.

12-chemistry-home

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