How many moles do you want? M x L = 0.1MHCl x 2.5L = 0.25 mols.
So you need 0.25 mols of the 12M HCl.
M = mols/L. You know M and you know mols; solve for L of the 12 M you need. Take that amount of 12M HCl and add water to make 2.5L of solution.
Describe how to make 2.5L of 0.1M HCL solution from 12M HCL concentrated solution and water.
Thank you
2 answers
How to prepared a 0.1MHCL from concentrated HCL