Problem: Which solution has the same number of moles of KCl as 75.00 mL of 0.250 M solution of KCl?A) 20.0 mL of 0.200 M solution of KClB) 25.0 mL of 0.175 M solution of KClC) 129 mL of 0.145 M solution of KClD) 50.0 mL of 0.125 M solution of KClE) 100 mL of 0.0500 M solution of KCl

We are asked to which solution has the same number of moles of KCl as 75.00 mL of 0.250 M solution of KCl

Recall dilution equation: 

$\boxed{\mathbf{mol}\mathbf{ }\mathbf{=}\mathbf{ }\mathbf{MV}}$

Calculate mol for 75.00 mL of 0.250 M solution of KCl

$$\begin{gathered} \mathbf{mol}\mathbf{ }\mathbf{KCl}\mathbf{=}\mathbf{ }\mathbf{MV} \\ \mathbf{mol}\mathbf{ }\mathbf{KCl}\mathbf{=}(0.25 \frac{\mathrm{mol}}{ \cancel{L}})(75 \cancel{\mathrm{mL}})\mathbf{\times }\frac{{\mathbf{10}}^{\mathbf{-}\mathbf{3}}\mathbf{ }\mathbf{ }\cancel{\mathbf{L}}}{\mathbf{1}\mathbf{ }\cancel{\mathbf{mL}}\mathbf{ }}\mathbf{ }\mathbf{=}\mathbf{ }\mathbf{0}\mathbf{.}\mathbf{0187}\mathbf{ }\mathbf{mol} \end{gathered}$$

Calculate mole for each option: