Given a surface potential ${}_0=-40mV,$ what is the surface charge in a $10$mMNaCl solution?

Plot the distribution of positive and negative ions from the surface. What happens to the potential and the ion distributions when the salt concentration increases to $100mM?$

Compare your answers in problem $3$ using the full Poisson$-$Boltzmann solution to the field and ion distributions calculated using the linearized Debye$-$H$$ckel solution.