Question

Sally has constructed a concentration cell to measure Ksp for MCln. She constructs the cell by adding 2 mL of 0.05 M M(NO3)n to one compartment of the microwell plate. She then makes a solution of MCln by adding KCl to M(NO3)n. She adds 7.903 mL of the resulting mixture to a second compartment of the microwell plate. Sally knows n = +2. She has already calculated [Mn+] in the prepared MCln solution using the Nernst equation. [Mn+] = 8.279 M

Required:
How many moles of [Cl-] must be dissolved in that compartment?

Answer 1

0.1309 mol

Step-by-step explanation:

From the given information:

The metal ion, two ions of
`M^(+)` reacted with Cl⁻ to form
`MCl_n` i.e. the compound formed is
`MCl_2`.

The concentration of the metal ion formed
`[M^+]` = 8.279 M

The concentration of the chlorine ion formed
`[Cl^-]` = 2 × 8.279 M

= 16.558 M

∴

We know that:

`\mathsf{Molarity = (no \ of \ moles )/(volume (mL))}`

The number of moles of
`[Cl^-]` =
`16.558 \ mol.L^(-1) * 7.903 \ mL * (1 \ L)/(1000 \ mL)`

= 0.1309 mol