Question

For a hypothetical reaction,
$4A+5B\rightleftharpoons 4P+6Q$
the equilibrium constant $K_c$ has units

• A. $\text{mol}{L}^{-1}$
• B. ${\text{mol}}^{-1}L$
• C. $(\text{mol}{L}^{-1}{)}^{-2}$
• D. $\text{unit less}$

Answer 1

The correct option is D $\text{unit less}$

For,
$4A+5B\rightleftharpoons 4P+6Q$

$K_c=\frac{\left[P{]}^4\right[Q{]}^6}{\left[A{]}^4\right[B{]}^5}$
$K_c=\frac{\left[mol{L}^{-1}{]}^4\right[mol{L}^{-1}{]}^6}{\left[mol{L}^{-1}{]}^4\right[mol{L}^{-1}{]}^5}$

$K_c=\frac{[mol{L}^{-1}{]}^6}{[mol{L}^{-1}{]}^5}$
$K_c=mol{L}^{-1}$