3. INTRODUCTION
Solution:
A solution is a homogeneous mixture composed of two
or more substances. In such a mixture, a solute is
dissolved in another substance, known as a solvent.
Solute:
The substance which dissolves in a solution.
Solvent:
The substance which dissolves another to form a
solution.
Saturation:
Saturation is the point at which a solution of a substance
can dissolve no more of that substance and additional
amounts of it will appear as a precipitate.
4. SOLUTIONS
It refers to a solution that contains more of the
dissolved material than could be dissolved by the
solvent under normal circumstances.
Types of solutions:
Percentage solution
Molar solution
Normal solution
5. PERCENTAGE SOLUTION
Weight/ Weight solution % (w/w)
This type of solution is rarely if ever prepared in the
laboratory since it is easier to measure volumes of
liquids rather than weigh the liquid on an analytical
balance.
Weight/volume solution % (w/v)
Weight-volume percentage, (sometimes referred to
as mass-volume percentage per 100 ml of the
resulting solution.
6. PREPARATION OF NaCL SOLUTION
Preparation of 10g (W/V) NaCl solution
Procedure:
Weigh of sodium chloride.
Pour it into a graduated cylinder containing about 80ml of
water.
Once the sodium chloride has dissolved completely add
water to bring the volume up to the final 100 ml.
Note:
Do not simply measure 100ml of water and add 10 of
sodium chloride. This will introduce error because adding
the solid will change the final volume of the solution and
throw off the final percentage.
7. VOLUME /VOLUME SOLUTION % (V/V)
Volume-volume percentage (abbreviated as %
v/v) describes the volume of the solute in ml per
100 ml of the resulting solution.
Procedure:
Calculate the required volume of solute.
Subtract the volume of solute from the total
solution volume.
Dissolve 30 ml sulfuric acid in a 70 ml of water to
bring final volume of solution up to 100ml.
8. NORMAL SOLUTION
Equivalent weight:
An equivalent weight is equal to the molecular weight
divided by the valence (replaceable H ions).
Normal:
A normal is one gram equivalent of a solute per liter of
solution.
Normality:
Normality is the total no of gram equivalents of the solute
present per liter of the solution.
Normal solutions:
The definition of a normal solution is a solution that
contains 1 gram equivalent weight per liter solution.
9. DILUTION OF SOLUTIONS
Simple Dilution:
A simple dilution is one in which a unit volume of a liquid
material of interest is combined with an appropriate
volume of a solvent liquid to achieve the desired
concentration.
Serial Dilution:
A serial dilution is simply a series of simple dilutions which
amplifies the dilution
factor quickly beginning with a small initial quantity of
material.
10. PREPARING SULFURIC ACID SOLUTION?
Always ADD ACID (AA) to water! A great amount of heat is
liberated when sulfuric acid is added to water.
The temperature of the solution will rise rapidly. In fact, the
temperature may rise so fast that the solution will boil and
possibly spatter a strongly acidic solution.
Consider immersing your mixing vessel in a bucket of ice to
control the solution temperature. Always add the acid to
water very slowly while stirring continuously.