Hi @keenap1! When we prepare diluted solutions, we have to stick on the volume of the desired diluted sample. In this example, we need to prepare 20 mL of 2 M solution however it was suggested to add 20 mL of water with 4 mL 10M HCl which results to a volume of 24 mL which is incorrect. So the answer is false.
Using the dilution formula, we can get volume of 10M needed for a 2 M solution.
V2=4 mL of 10M HCl
Meaning we have to put 16 mL of water with 4 mL of HCl to get 20 mL of 2M solution. Not 20 mL of water in 4 mL 10M HCl.
I hope that makes sense!