Question

A 35 ml 2.40 M HCl solution is diluted by adding water till the molarity of the solution decreases to 0.30 M. Determine
the volume of water added.​

Answer 1

A 35 ml 2.40 M HCl solution is diluted by adding water till the molarity of the solution decreases to 0.30 M. we have to determine the volume of water added.

solution :

in case of dilution, no of moles of solute remains constant.

so, no of moles of solute before dilution = no of moles of solute after dilution

or, concentration before × volume before dilution = concentration after dilution × volume after dilution .

let V ml water is added into solution.

or, 2.4 M × 35ml = 0.3M × (35 + V)ml.

or, 8 × 35 = (35 + V)

or, 560 = 35 + V

or, V = 525 ml

hence, 525ml water is added into the solution.