Question

Which of the following is not physical equilibrium?

• A. $Ice\leftrightharpoons water$
• B. $I_2\left(s\right)\leftrightharpoons I_2\left(g\right)$
• C. $S\left(l\right)\leftrightharpoons S\left(g\right)$
• D. $3O_2\left(g\right)\leftrightharpoons 2O_3\left(g\right)$

Answer 1

The correct option is D $3O_2\left(g\right)\leftrightharpoons 2O_3\left(g\right)$

In physical equilibrium there should be a change in the physical state of the compounds involved in the equilibrium.
In $3O_2\left(g\right)\leftrightharpoons 2O_3\left(g\right)$
there is no change in the physical state. $O_2$ is gas and $O_3$ is also in gaseous state.
$\therefore$ It is not a physical equilibrium.