To calculate the volume occupied by 2.4 moles of chlorine gas, we can use the ideal gas equation:

```

PV = nRT

```

where:

* P is the pressure (in atmospheres)

* V is the volume (in liters)

* n is the number of moles

* R is the ideal gas constant (0.08206 L * atm / mol * K)

* T is the temperature (in Kelvin)

Assuming standard temperature and pressure (STP), which are 0°C (273.15 K) and 1 atm, we can calculate the volume occupied by 2.4 moles of chlorine gas:

```

V = nRT/P

= 2.4 moles * 0.08206 L * atm / mol * K * 273.15 K / 1 atm

= 55.12 L

```

Therefore, 2.4 moles of chlorine gas occupy a volume of approximately 55.12 liters at STP.