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 6.380 mL of the resulting mixture to a second compartment of the microwell plate.
Sally knows n (the charge on the metal ion) = +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

Answer:

0.1056 mole

Explanation:

As Sally knows that the charge on the metal ion is n = +2

$MCl_n=MCl_2$

In that compartment $[M^{n+}]=[m^{2+}]=8.279 \ M$

The volume of the $MCl_n$ taken in that compartment = 6.380 mL

So, the number of moles of $M^{2+} = 8.279 \times 6.380$

                                                      = 52.82 m mol

                                                      = 0.05280 mol

$MCl_n \rightarrow M^{n+}+nCl^-$

But n = 2

Therefore, moles of $Cl^-$ = 2 x moles of $M^{n+}$

                                       = 2 x 0.05282

                                       = 0.1056 mole