Question

10mL volume of 75mM EtOH is necessary for an experiment. What volumes of 1M EtOH and water should be mixed to obtain the working concentration?

Answer 1

Answer: Volume of the 1M EtOH and water should be 0.75 ml and 9.25 ml respectively to obtain the working concentration.

Step-by-step explanation:

According to the dilution law,

`C_1V_1=C_2V_2`

where,

`C_1` = molarity of stock solution = 1M

`V_1` = volume of stock solution = ?

`C_2` = molarity of diluted solution = 0.075 M (1mM=0.001M)

`V_2` = volume of diluted solution = 10 ml

Putting in the values we get:

`1M* V_1=0.075M* 10ml`

`V_1=0.75ml`

Thus 0.75 ml of 1M EtOH is taken and (10-0.75)ml = 9.25 ml of water is added to make the volume 10ml.

Therefore, volume of the 1M EtOH and water should be 0.75 ml and 9.25 ml respectively to obtain the working concentration