Question

Write the unit of equilibrium constant $\left(K_c\right)$ for the given reaction.
$C\left(s\right)+\frac{1}{2}{O}_2\left(g\right)\to C{O}_2\left(g\right)$

• A. $\left(mol/L\right)$
• B. $(mol/L{)}^{\frac{3}{2}}$
• C. $(mol/L{)}^{\frac{-1}{2}}$
• D. $(mol/L{)}^{\frac{1}{2}}$

Answer 1

The correct option is D $(mol/L{)}^{\frac{1}{2}}$

Equilibrium constant $K_c$ is proportional to the active masses of the products and reactants.
$C\left(s\right)+\frac{1}{2}{O}_2\left(g\right)\to C{O}_2\left(g\right)$
$\text{For this reaction,}{K}_c=\frac{\left[C{O}_2\right]}{[O_2{]}^{\frac{1}{2}}}$
Active mass of solids are considered as 1.
where $\left[C{O}_2\right]$, $[O_2{]}^{\frac{1}{2}}$ are the molar concentations having a unit of mol/L
So, unit of $K_c=\frac{mol/L}{(mol/L{)}^{\frac{1}{2}}}$
$K_c=(mol/L{)}^{\frac{1}{2}}$