The effect of temperature on the critical micelle concentration CMC of a surfactant and its impact on the surface tension of a liquid medium can be complex and depends on the specific surfactant and liquid medium involved. However, some general trends can be observed.1. Effect of temperature on CMC:As the temperature increases, the CMC of a surfactant typically decreases. This is because an increase in temperature leads to an increase in the kinetic energy of the surfactant molecules, which in turn enhances their movement and ability to interact with each other. As a result, the surfactant molecules can more easily aggregate and form micelles at lower concentrations.However, this trend may not always hold true for all surfactants, especially those with strong polar head groups or hydrogen bonding capabilities. In such cases, the effect of temperature on CMC can be more complicated and may even show an opposite trend.2. Impact on surface tension:The formation of micelles by surfactants plays a crucial role in reducing the surface tension of a liquid medium. When the temperature increases, the CMC decreases, as mentioned earlier. This means that micelles can form at lower surfactant concentrations, which can lead to a more significant reduction in surface tension.As the temperature continues to increase, the surfactant molecules gain more energy, which can cause them to desorb from the liquid-air interface and re-enter the bulk liquid phase. This can lead to a decrease in the surface-active species at the interface, resulting in an increase in surface tension. However, this effect is generally observed at temperatures much higher than the normal working range of surfactants.In summary, the effect of temperature on the CMC of a surfactant and its impact on the surface tension of a liquid medium can be complex and depends on the specific surfactant and liquid medium involved. Generally, an increase in temperature leads to a decrease in CMC and a more significant reduction in surface tension, but this trend may not hold true for all surfactants, and the effect can be more complicated at higher temperatures.