Question

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

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

Answer 1

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

Equilibrium Constant $K_c$ is proportional to the active masses of the products and reactants.
$C\left(s\right)+\frac{1}{2}{O}_2\left(g\right)\to C{O}_2\left(g\right)$
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 concentrations having a unit of $\text{(mol/L)}$ .
So, unit of $K_c=\frac{\text{(mol/L)}}{{\text{(mol/L)}}^{\frac{1}{2}}}$
$K_c={\text{(mol/L)}}^{\frac{1}{2}}$