If I start with 400 mL a 4.0 solution of HCl, and add 100 mL of water to the solution what is the new molarity?

If I start with 400 mL a 4.0 solution of HCl, and add 100 mL of water to the solution what is the new molarity?

Explanation:

If I start with 400 mL a 4.0 solution of HCl, and add 100 mL of water to the solution what is the new molarity?

i believe you are right for all except the 3rd ( look at sqdancefan his answer is much better)