For the reaction A+3B=======2C+D?

Question

Write down an equation for the concentration-based equilibrium constant (kc) and hence deduce the units of the constant for this reaction system.

Answer 1

Keq = [C] ^2 [D] / [A] [B]^3
The concentration of each specie may be expressed in mol/L
( mol/L)^2 ( mol/L) / ( mol/L) ( mol / L )^3
=> 1 / mol /L => or L / mol
or M ^-1

Answer 2

Dr A is right. The other answer is wrong.

The units will vary from case to case, depending on the number of species on each side of the equation.

Answer 3

Kc = [c]2[d]
[a][b]3

the Kc has no units b/c its a ratio