Write the rate expressions for the forward and reverse reactions and their units for the given reversible, elementary reaction A + B <=> C + 2D.

Here are the solutions for the reaction rate expressions and units.

The given reversible, elementary reaction is:
$A + B \leftrightarrow C + 2D$

Step 1: Write an expression for the rate of reaction of A ($r_A$).
For an elementary reaction, the rate law can be written directly from the stoichiometry.
The forward reaction is $A + B \to C + 2D$, with rate $r_f = k_f C_A C_B$.
The reverse reaction is $C + 2D \to A + B$, with rate $r_r = k_r C_C C_D^2$.
However, the provided boxes for the rate expression show $