Question

0.5M na2co3 मानक विलयन का 250 ml घोल तैयार करें

Answer 1

First of all we have to calculate the quantity of Na2CO3 to be mixed in the given volume of water.

To calculate that we need to use the formula,

Quantity of Na2CO3 = (Molarity) × (Volume of solution in litres) × (molar mass of Na2CO3)

So given volume of solution = 250 ml = 0.25 litres

and the molar mass of Na2CO3 = (2 × 23) + (1 × 12) + (3 × 16)

                                                      = 46 + 12 + 48

                                                      = 106

Therefore, quantity of Na2CO3 = (0.5) × (0.25) × (106)

                                                     = 13.25 g

Now to make the solution, weigh the quantity of Na2Co3 that we have calculated above. Pour the distilled water in a beaker, 10-20 ml less than the actual volume we have to make and then add the weighed quantity of Na2CO3. Mix it well with a stirrer so that the salt dissolves completely. Now, pour the solution in a graduated cylinder and complete the final volume by adding the required amount of distilled water.