Answer
$50\;mL$.
Work Step by Step
The given values are
Base $B=1000\;mL$.
Rate $R=5$.
Let the pure Lysol is $P=x$
The formula is
$\Rightarrow \frac{P}{B}=\frac{R}{100}$
Substitute all the values.
$\Rightarrow \frac{x}{1000\;mL}=\frac{5}{100}$
Cross multiply.
$\Rightarrow 100x=5000\;mL$
Divide both sides by $100$.
$\Rightarrow x=50\;mL$.
