Answer: 4.5L of chlorine gas is generated.
Explanation: First we write the balanced equation of reaction of fluorine gas with HCl at stp
F2 + 2HCl ⇒ 2HF + Cl2
We can solve by comparing mole ratios of fluorine gas and chlorine gas, but a shorter method is to Use Gay-Lussac's law of combining volumes which state that when gases react, they do so in volumes which are in simple ratio to one another and to the volumes of the products formed, if gaseous, provided temperature and pressure remains constant.
From the balanced equation,
1 L of F2 produces 1 L of Cl2
4.5 L of F2 will produce (4.5 X 1)/1 L of Cl2
=4.5 L of Cl2
