Question

Srivani dissolved 50 g of salt in 150 mL of water to carry out an experiment. She needs another 240 mL of the 'same' solution for another experiment. How much salt does she need to make the 'same' solution?

• A. 60
• B. 80
• C. 120
• D. 240

Answer 1

The correct option is A

60

1 mL of water has a mass of 1 g. So, the mass of 150 mL of water = 150 g.

Mass of solution = mass of solute + mass of solvent = 50 + 150 = 200 g

The concentration of the first solution that Srivani prepared $=\frac{massofthesolute}{massofthesolution}\times 100\%=\frac{50g}{200g}\times 100=25\%$

So, the mass of the salt required $=concentration\times massofthesolution=\frac{25}{100}\times 240g=60g$