#H_2(g) + Cl_2(g) rarr 2HCl(g)# The give reaction occurs at constant pressure...which is the only viable observation?
#"1. Pressure will increase in reaction."#
#"2. Mass will increase in reaction."#
#"3. Pressure will decrease in reaction."#
#"4. Mass is conserved in the reaction."#
YOu have been given the chemical equation:
There are 2 equiv (moles if you like) of gaseous product, and 2 equiv gaseous reactant. Clearly, mass is conserved in a chemical reaction, as are pressure and volume in this scenario, because temperature was specified to be constant.