Question

I have made 15 ml of 200 mM CaCl2 stock and need to make 40 ml of 50mM for my experiment. How much of my concentrated stock solution (in milliliters) and how much water do I need to mix to make the 40 ml of 50mM CaCl2 ?

Answer 1

Answer: 10 ml of 200 mM $CaCl_2$ is required and 30 ml of water is required.

Explanation:

According to the dilution law,

$C_1V_1=C_2V_2$

where,

$C_1$ = concentration of stock solution = 200mM

$V_1$ = volume of stock solution = ?

$C_2$ = concentration of resulting solution= 50mM

$V_2$ = volume of another acid solution= 40 ml

$200\times x=50\times 40$

$x=10ml$

Thus 10 ml of 200 mM $CaCl_2$ is required and (40-10) ml = 30 ml of water is to be added to make 40 ml of 50mM $CaCl_2$.