Question

250 ml of a sodium carbonate solution contains 2.65grams of Na2Co3. 10ml of this solution is added to x ml of water to obtain 0.001M Na2Co3 solution. What is the value of x in ml?

Answer 1

Number of moles of Na2CO3 = 2.65/106
Volume of solution in litres = 0.25 lit = 1/4 lit.
∴ Molarity of Na2CO3 solution = 2.65/106 × 4/1 = 0.1 M
V2M2=V1M1
V2× 0.001 = 10 x 0.1
∴ Volume of final solution prepared,
V2 = 10x0.1/0.001 = 1000 ml
∴ Volume of water added =1000-10 =990 ml.