Select each process that produces an increase in the entropy of the system:
Check all that apply.

 HCl(g) + NH3(g) → NH4Cl(s)
 
 2 SO2(g) + O2(g) → 2 SO3(g)
 
 CaO(s) + CO2(g) → CaCO3(s)
 
 CO2(s) → CO2(g)