When a reaction is at chemical equilibrium, what is true about the forward and reverse reactions?

1 Answer
Dec 10, 2016

The condition of equilibrium specifies equality between forward and reverse rates.

Explanation:

#A+BrightleftharpoonsC+D#

There is a rate forward, #k_f[A][B]#, and a rate backward, #k_r[C][D]#.

At #"equilibrium"# these rates are equal, i.e.

#k_f[A][B]=k_r[C][D]#, on rearrangement,

#k_f/k_r=([C][D])/([A][B])#

The quotient, #k_f/k_r#, is better know as #K_"eq"#, the equilibrium constant. It must be experimentally measured.