Question

how much of a 12 m hcl solution is needed to prepare 20.0 l of a 0.25 m solution?

Explanation:

Step1: Use the dilution formula $M_1V_1 = M_2V_2$.

Let $M_1$ be the initial molarity, $V_1$ be the initial volume, $M_2$ be the final molarity and $V_2$ be the final volume. Here, $M_1 = 12\ M$, $M_2=0.25\ M$, $V_2 = 20.0\ L$.

Step2: Rearrange the formula to solve for $V_1$.

$V_1=\frac{M_2V_2}{M_1}$

Step3: Substitute the values into the formula.

$V_1=\frac{0.25\ M\times20.0\ L}{12\ M}=\frac{5}{12}\ L\approx0.42\ L$

Answer:

$0.42\ L$