Question

0.4 mole of HCl and 0.6 mole of MgCl2 were dissolved to have 400 mL of the solution. The molarity of CI- in the final solution is​

Answer 1

given info : 0.4 mole of HCl and 0.6 mole of MgCl₂ were dissolved to have 400 mL of the solution.

To find : the molarity of Cl¯ ion in the final solution.

Solution : here in one mole HCl, one mole of Cl¯ ions is present and in one mole of MgCl₂ , 2 moles of Cl¯ ions are present.

So, 0.4 mole HCl contains 0.4 mole of Cl¯ ions

and 0.6 mole of MgCl₂ contains 2 × 0.6 = 1.2 moles of Cl¯ ions.

So, total no of Cl¯ ions = 0.4 + 1.2 = 1.6

Volume of solution = 400 mL

Molarity of Cl¯ ions = no of moles of Cl¯ ions/volume in L

= 1.6/(400/1000)

= 1600/400

= 4M

Therefore the molarity of Cl¯ ion in the final solution is 4 molar.