Answer:
The answer to your question is 55.224 g of NiClâ‚‚
Explanation:
I will solve it and then I compare the results.
Data
Volume = 0.8 l
Molarity = 0.531
substance = NiClâ‚‚
Process
1.- Calculate the molar mass of NiClâ‚‚
NiClâ‚‚ = 59 + (35.5 x 2)
     = 130 g
2.- Calculate the number of moles
Molarity = moles / volume
-Solve for moles
 moles = Molarity x volume
-Substitution
 moles = 0.531 x 0.8
-Result
 moles = 0.4248
3.- Convert the moles to mass
          130 g -------------------- 1 mol of NiCl₂
           x   -------------------- 0.4248 moles
              x = (0.4248 x 130) / 1
-Simplifying
             x = 55.224 / 1
-Result
            x = 55.224 g of NiCl₂
4.- We need 55.224 g of NiClâ‚‚ to prepare 0.8l of a solution 0.531 M.
You have similar results, just our molar mass is different.