# What does the symbol of a double arrow indicate in a chemical reaction?

Mar 16, 2017

That the reaction has reached equilibrium..........

#### Explanation:

And if equilibrium applies to the following reaction:

$A + B r i g h t \le f t h a r p \infty n s C + D$,

then by definition, ${k}_{f} \left[A\right] \left[B\right] = {k}_{r} \left[C\right] \left[D\right]$

And we can write, ${k}_{r} / {k}_{f} = {K}_{\text{equilibrium}} = \frac{\left[C\right] \left[D\right]}{\left[A\right] \left[B\right]}$, where ${k}_{r} / {k}_{f} = {K}_{\text{equilibrium}}$ is the thermodynamic equilibrium constant. This must be measured, and has been measured meticulously for many chemical equilibria.