Question

The teacher instructed three students A', 'B' and 'C' respectively to prepare
a 50 (mass by volume) solution of sodium hydroxide (NaOH). 'A' dissolved
50g of NaoH in 100 mL of water, 'B dissolved 50g of NaOH in 100g of
water while'C dissolved 50g of NaOH in water to make 100 mL of solution.
Which one of them has made the desired solution and why?​

Answer 1

Answer:

'C' has made the desired solution

Mass by volume %=

Volume of solution

Mass of solute

×100

=

100

50

×100

=50% mass by volume

50 % Mass by volume means 50g of NaOH is dissolved in 100ml of solution. So C makes the solution. A has taken 100 ml of water itself. Hence, A does not make the desired solution. B has taken 100 gm of water. Thus, for B also, the solution will not be 50% mass by volume.