give proper method without using mtlab code

The stagnant liquid B in a container that is 10cm high (L=10cm) is exposed to the non reactant gas A at time t=0. The concentration of A, dissolved physically in B, reaches CAO=0.01m3mol at the interface instantly and remains constant. The diffusion cocfficient of A in B is DAB=2109m2/s. Determine the evolution of concentration of A within the container. Plot the flux of A dissolved in B against time. Initial condition CA(Z,O)=0 Boundary condition at Z=OCCAO(t)=CAO at Z=L7CZL=0 Use explicit method. The stagnant liquid B in a container that is 10cm high (L=10cm) is exposed to the non reactant gas A at time t=0. The concentration of A, dissolved physically in B, reaches CAO=0.01m3mol at the interface instantly and remains constant. The diffusion cocfficient of A in B is DAB=2109m2/s. Determine the evolution of concentration of A within the container. Plot the flux of A dissolved in B against time. Initial condition CA(Z,O)=0 Boundary condition at Z=OCCAO(t)=CAO at Z=L7CZL=0 Use explicit method