# H_2(g) + Cl_2(g) rarr 2HCl(g) The give reaction occurs at constant pressure...which is the only viable observation?

## $\text{1. Pressure will increase in reaction.}$ $\text{2. Mass will increase in reaction.}$ $\text{3. Pressure will decrease in reaction.}$ $\text{4. Mass is conserved in the reaction.}$

##### 1 Answer
Oct 23, 2016

$\text{Option 4}$ is the only viable answer.

#### Explanation:

YOu have been given the chemical equation:

${H}_{2} \left(g\right) + C {l}_{2} \left(g\right) \rightarrow 2 H C l \left(g\right)$

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. $\text{Option 4}$ is the only starter.