Question

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

Answer 1

Student 'C' has made it correctly because 50% (mass by volume) means 50 g of solute is dissolved in 100 mL of solution and not in 100 mL of solvent.
Student 'A' dissolved 50 g of NaOH in 100 mL of water (solvent) which is incorrect.
Student 'B' dissolved 50 g of NaOH in 100 g of water (solvent) which is also incorrect.