Answer
I would need 11.2 L of gaseous hydrogen and 11.03 L of gaseous chlorine.
Work Step by Step
We use unit conversions to find:
Hydrogen:
$1.0078g \times \frac{1L}{0.0899g} = 11.2 L$
Chlorine:
$35.45g \times \frac{1L}{3.214g} = 11.03 L$