A solution is a homogeneous mixture composed of only one phase. In such a mixture, a solute is a substance dissolved in another substance called as the solvent. The concentration of a solute in a solution is a measure of how much of that solute is dissolved in a solvent.
Standard solutions are those in which the exact amount of a substance presents in a definite volume of solution. To prepare the standard solution, a known weight of solute is measured on a well-calibrated weighing scale and then dissolved in a solvent (usually distilled water) to make up a specific volume.
Normality (N) is one of the commonly used units that determine the concentration of the solution that expresses the gram equivalent weight of solute per liter of the solution. In other words, Normality is simply the number of active grams of a solute per liter of the solution.
The 0.1 N Sodium Carbonate solution is prepared as follows…..
- Weighing scale
- Beaker/Volumetric flask
- Measuring cylinder
- Sodium Carbonate (Na2CO3)
- Distilled water
Molecular weight of Na2CO3 – (23×2) + 12 + (3×16) = 46 + 12 + 48 = 106 gm
Normality = Weight / Equivalent weight × 1000 / Volume (in ml)
0.1 = (X/106/2) × (1000 / 500)
0.1 = (X × 2 / 106 ) × (1000 / 500)
X = 0.1 × 53 × 0.5 = 2.65 gm
X = 2.65 gm
⇒ Weigh 2.65 gm of Na2CO3 with the help of weighing scale.
⇒ Then take 200 ml of distilled water in Beaker / Volumetric flask and to this add 2.65 gm of Na2CO3.
⇒ If using a beaker, mix the contents well by using a stirrer and If using the Volumetric flask mix well the contents by gently swirling the flask.
⇒ When it dissolves completely then add the Distilled water and make the final volume of 500 ml.
⇒ Then again mix it with the help of stirrer in case of the beaker or by swirling in case of volumetric flask.
⇒ Weigh accurately 2.65 gm anhydrous Sodium Carbonate on a well-calibrated weighing balance.
⇒ Last few milliliters of the distilled water should be added using a pipette to avoid volume error.
⇒ Transference of the weighed substance into a beaker or volumetric flask should be done very carefully and not a single crystal be allowed to fall outside.
⇒ Sodium carbonate solutions are strongly alkaline and corrosive. It can cause severe skin and eye irritation upon contact.
⇒ Inhalation of sodium carbonate dust or fumes can cause irritation of mucous membranes and the respiratory tract, and lead to severe coughing and shortness of breath. High concentrations can damage the eye and cause skin burns.