Question

The volume of water must be added to 100 ml of 0.5 M NaOH solution to get 0.2M solution is

Answer 1

Explanation:

molarity of the solution initially : M1 .5 M

volume of the solution initially : V1 100 ml .1 litre

molarity of solution after dilution M2 : . 2M

volume of the solution after dilution V2: to be determined

Formula used: V1M1 equals to V2M2

then V2 equals to V1M1/M2 equals to .1 x.5/.2 equals to .25 litres equals to 250 ml

volume of solvent to be added to get the dilute solution : 250 ml - 100 ml equals to 150 ml

Ans : 150 ml

Answer 2

Answer:

The volume of water must be added to 100 mL of 0.5 M NaOH solution to get 0.2 M solution is

Solution

Solution - I (Initial or before dilution)

Solution – II (Final after dilution)

Volume of NaOH solution=V1=100 mL

Volume of NaOH =V2

Molarity,M1=0.5 M

Molarity,M2=0.2 M

According to Dilution Law,

M1V1=M2V2

The final volume of NaOH is

V2=M1V1M2=0.5×1000.2=250mL

Volume of water to be added =V2 − V1

=250−100

=150 mL