Preparation of Standard Solutions

The main aim of this experiment is to prepare a standard solution of 0.1 M sodium carbonate.

Let us understand first what is the standard solution. Standard solution is a solution of accurately known concentration of substance. A known mass of solute dissolved in a specific volume of solvent is known. It is prepared using a standard substance, such as a primary standard.

To perform this experiment, we require apparatus and materials such as digital balance, glass rod, funnel, volumetric flask, distilled water, watch glass and sodium carbonate.

To standardize the 0.1 M sodium carbonate solution, we have to follow the given procedure.

• Place an empty, clean and dry watch glass on a digital balance and press the tare button to reset the value to zero. 

• Weigh 2.6500 g sodium carbonate on the watch glass. 
• Transfer sodium carbonate carefully from the watch glass into a clean and dry volumetric flask through the funnel. 
• Spray the mouth and the tip of the funnel with water to transfer the sticking particles, if any, into the volumetric flask. While doing so, add water in small amounts so that its volume in the flask does not exceed ¼ th of the volume of the volumetric flask. 
• Add more distilled water with shaking. Make up the volume with distilled water to the etched mark by adding the last few mL dropwise. 
• Stopper the flask and shake it thoroughly to make the solution uniform throughout. 
• Label it as 0.1 M sodium carbonate solution.

In this experiment we conclude that

1. A volumetric flask is the standard apparatus to prepare the standard solution.
2. Calculate the required amount of sodium carbonate salt by using the formula:

           Mass of solute (sodium carbonate) = Molarity x Molar mass x Volume (in L)

i.e. Mass of sodium carbonate = 0.1 x 106 x 0.25 = 2.6500 g

To standardize the 0.1 M sodium carbonate solution, 2.65 g is required to dissolve in 250 mL. 

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