Question

Calculate the final concentration of NaCl after 1.5 litres of 0.100M NaCl solution is diluted to 3.5 litres with water with 3.5 litres of water

(A) 0.214 M, 0.714 M (B) 0.5 M, 0.7 M
(C) 0.414 M, 0.614 M (D) 0.0314 M, 0.414 M

Answer 1

In this problem, we can use the formula:

m1v1 = m2v2

Where:

m1 = Initial concentration (molarity)

v1 = Initial volume

m2 = Final concentration (molarity)

v2 = Final volume



m1v1 = m2v2

0.1 x 1.5 = m2 x 3.5

0.15 = 3.5m2

m2 = 0.15/3.5

m2 = 0.043M


NOTE

In case 3.5 litres of water is added, the final volume would be 1.5+3.5 =5 litres

and the  calculation would be:

0.1 x 1.5 = m2 x 5


0.15 = 5m2

m2 = 0.15/5

m2 = 0.03M