Response:
To reach the answer, 465.6 mg of MgI₂ is required.
Detailed Explanation:
We need to establish the moles of ion I⁻ in the resulting solution.
C = n/V -> n = C x V = 0.2577 (L) x 0.1 (mol/L) = 0.02577 mol.
In the initial solution, there was 0.087 M KI, which we can similarly convert into moles, yielding 0.02242 mol.
This indicates we require an additional amount of 0.02577 - 0.02242 = 0.00335 mol of I⁻. Since each molecule of MgI₂ produces two I⁻ ions, we divide 0.00335 by 2 to determine the moles of MgI₂, giving us 0.001675 mol.
Consequently, the quantity of MgI₂ to be added is:
Weight of MgI₂ = 0.001675 mol x 278 g/mol = 0.4656 g = 465.6 mg