Question

The teacher instructed two students A, and B respectively to prepare a 50% (mass by volume) solution of sodium hydroxide (NaOH). Student A dissolved 50g of NaOH in 100 mL of water. The student B dissolved 50g of NaOH in water to make 100mL of solution. Which one of them has made the desired solution and Why?

Answer 1

Answer:

student B has made the desired solution

Answer 2

Answer:

Student 'B' made the desired solution.

Explanation:

NaOH that Student A dissolved= 50g

Water amount of Student A = 100ml

(Here NaOH is the solute and Water is the solvent.)

Mass of NaOH(solute)=50g

Volume of Water( solvent)=100ml

So, the solution percentage of Student A

= mass of solute ÷ volume of solution ×100

= mass of solute ÷ mass of solute + volume of solvent

=50g÷50g+100ml ×100

=50 ÷ 150 × 100

= 33.33%

Now,

NaOH that Student B dissolved=50g

Solution amount of Student B =100ml

(Here NaOH is the solute and the solution is directly given that is 100ml)

So, mass of NaOH(solute) = 50g

volume of Solution = 100ml

So, the solution percentage of Student B

= mass of solute ÷ volume of solution ×100=

= 50 g ÷ 100ml × 100

= 50%

So Student B prepared 50% solution of NaOH.

So,Student B has made the desired solution.

Hope it makes you understand clearly.