Answer:
Molarity of [tex]Fe^{2+}[/tex] solution is 0.0928 M.
Explanation:
Balanced equation: [tex]5Fe^{2+}+MnO_{4}^{-}+8H^{+}\rightarrow 5Fe^{3+}+Mn^{2+}+4H_{2}O[/tex]
Number of moles of [tex]MnO_{4}^{-}[/tex] in 10.8 mL of 0.0215 M [tex]MnO_{4}^{-}[/tex] solution
= [tex]\frac{0.0215}{1000}\times 10.8moles[/tex] = 0.000232 moles
Let's assume molarity of [tex]Fe^{2+}[/tex] solution is S(M)
Number of moles of [tex]Fe^{2+}[/tex] in 12.50 mL of S(M) [tex]Fe^{2+}[/tex] solution
= [tex]\frac{S}{1000}\times 12.50moles[/tex] = 0.0125S moles
According to balanced equation, 5 moles of [tex]Fe^{2+}[/tex] react with 1 mol of [tex]MnO_{4}^{-}[/tex]
So, 0.0125S moles of [tex]Fe^{2+}[/tex] react with [tex]\frac{0.0125S}{5}[/tex] moles of [tex]MnO_{4}^{-}[/tex]
Hence, [tex]\frac{0.0125S}{5}=0.000232[/tex]
or, S = 0.0928
So, molarity of [tex]Fe^{2+}[/tex] solution is 0.0928 M.
