Dilution Problem 11 We had 50 ml of a 3M solution of NaCl an

Dilution Problem

11. We had 50 ml of a 3M solution of NaCl and we have lost by evaporation 5 ml of water. What is the new concentration of the solution?

Ans:

Molecular weight of Nacl = 23+35.5=58.5x3

175.5g in 1000ml=3M Nacl

8.775g in 50 ml =3 M Nacl

Therefore, 8.775 g in 45ml= 3.33M Nacl

Molar concentration (C)= m/v X 1/MW

C=8.775/45 X 1/58.5

=0.195 X 0.017=0.0033mM

C=3.33 mM