This is a dilution equation where a certain volume from a more concentrated solution is diluted with distilled water to make a less concentrated solution. We can use the dilution equation as follows
c1v1 = c2v2
where c1 is concentration and v1 is volume of the more concentrated solution
and c2 is concentration and v2 is volume of the diluted solution to be prepared
where c1 - 12 M
c2 - 1.2 M
v2 - 20 mL
we need to find v1 , that is the volume that should be taken from the 12 M solution to make 20 mL of 1.2 M solution
substituting these values in the equation
12 M x v1 = 1.2 M x 20 mL
v1 = 2 mL
therefore 2 mL of 12 M solution should be taken to the graduated cylinder and diluted up to 20 mL to make a 1.2 M solution
