**Solution:**

To solve this problem, we can use the ideal gas law, which states that the pressure of a gas is directly proportional to its volume and inversely proportional to its temperature, assuming constant moles of gas. The equation for the ideal gas law is:

**PV = nRT**

Where:
P = pressure of the gas (in atm)
V = volume of the gas (in liters)
n = number of moles of gas
R = ideal gas constant (0.0821 L atm/(mol K))
T = temperature of the gas (in Kelvin)

In this problem, we are given the initial pressure (0.50 atm), the initial volume (1.2 L), and the final pressure (3 atm). We are asked to find the final volume of the can.

**Step 1: Convert the given pressures to Kelvin**

Since the ideal gas law requires temperature to be in Kelvin, we need to convert the given pressures from atm to Kelvin. We can do this by using the equation:

**P1 / T1 = P2 / T2**

Where P1 and P2 are the initial and final pressures, and T1 and T2 are the initial and final temperatures in Kelvin.

**Step 2: Solve for the final temperature**

Rearranging the equation, we have:

**T2 = (P2 * T1) / P1**

Substituting the given values, we get:

**T2 = (3 atm * T1) / 0.50 atm**

**Step 3: Solve for the final volume**

Now that we have the final temperature, we can use the ideal gas law equation to solve for the final volume. Rearranging the equation, we have:

**V2 = (P1 * V1 * T2) / (P2 * T1)**

Substituting the given values, we get:

**V2 = (0.50 atm * 1.2 L * T2) / (3 atm * T1)**

**Step 4: Calculate the final volume**

Substituting the value of T2 from Step 2, we get:

**V2 = (0.50 atm * 1.2 L * (3 atm * T1) / 0.50 atm) / (3 atm * T1)**

Simplifying the equation, we find:

**V2 = 1.2 L**

Therefore, the volume of the hair spray can is 1.2 L.

2.4 litter