The BET Brunauer-Emmett-Teller theory of multilayer adsorption is used to determine the surface area of adsorbent materials. The BET equation is:n = n_m * C * P / [ 1 - P * C - 1 + P ]where n is the adsorption capacity, n_m is the monolayer capacity, C is the BET constant, and P is the relative pressure P/P0 .In this case, we are given the adsorption capacity 5.6 mmol/g and the monolayer capacity 4.2 mmol/g . However, we do not have enough information to solve for the surface area directly, as we need the BET constant C and the relative pressure P to do so.If you can provide the BET constant and the relative pressure, we can then calculate the surface area of the adsorbent material.