What volume of chlorine is required to produce 25.4?

From this reaction equation:

Cu + Cl2 → CuCl2

so 1 mol CuCl2 will produce from 1 mol Cl2

when the moles of CuCl2 = mass / molar mass 

                                            = 25.4 g / 134.45 g/mol

                                            = 0.189 moles 

∴0.189 moles of CuCl2 will produce from 0.189 moles Cl2

∴ Volume of 0.189 moles of Cl2 is :

 V = nRT/P

when n is the number of moles = 0.189 moles

R is ideal gas constant = 0.0821 

T temperature in Kelvin = 18 + 273 = 291 K

P is the pressure = 2.13 atm

by substitution:

∴ V = 0.189 * 0.0821 * 291 / 2.13

    = 2.12 L