Question

how much h2o will be added in 100 ml 0.3m aqueous nacl solution so that resultant molarity of solutions becomes 0.1M​

Answer 1

To find:

Volume of water (H2O) to be added in 100 ml 0.3M aqueous NaCl solution so that resultant molarity of solutions becomes 0.1M ?

Calculation:

It is best to apply the following expression in these cases (the product of volume of solution and strength will be constant):

$\therefore \: V1 \times S1 = V2 \times S2$

$\implies \: 100 \times 0.3= (100 + x) \times 0.1$

$\implies \: 30= (100 + x) \times 0.1$

$\implies \: (100 + x) = \dfrac{30}{0.1}$

$\implies \: (100 + x) = 300$

$\implies \: x = 300 - 100$

$\implies \: x = 200 \: ml$

So, 200 mL of water has to be added to get the required strength of NaCl.