Which of the following statements is true regarding adsorption isotherms?
They show the variation in the amount of adsorbent with pressure at constant temperature
They show the variation in the amount of adsorbent with temperature at constant pressure
They show the variation in the amount of adsorbate with pressure at constant temperature
They show the variation in the amount of adsorbate with temperature at constant pressure
Adsorption isotherms show the variation in the amount of adsorbate (gas) with pressure at constant temperature.