molarity concept

"Molarity" of a solution is the number of moles of the solute in 1 dm3 of the solution.

For example
For a solution of molarity y mol dm-3 (y M), 1 dm3 of the solution contains y moles of the solute.
If volume = 1 dm3, number of moles of solute = y mol.
If volume = 2 dm3, number of moles of solute = 2y mol
If volume = 3 dm3, number of moles of solute = 3y mol
.........
If volume = V dm3,
number of moles of solute = V x y mol
number of moles of solute = y x V mol
number of moles of solute = Molarity x (Volume of solution in dm3)