Q1: Below is given an equilibrium moisture curve of a substance. State which regions represent free moisture and unbound moisture respectively.

ANS:A - II, III

Without the actual equilibrium moisture curve provided, it's difficult to precisely identify the regions representing free moisture and unbound moisture. However, I can explain the concepts and how they might appear on such a curve.

1. Free Moisture: Free moisture refers to moisture that exists on the surface of a substance and can be easily removed by physical means such as evaporation. On an equilibrium moisture curve, the region representing free moisture would typically be the initial portion of the curve where there is a steep increase in moisture content with increasing humidity or moisture concentration in the surrounding environment. This portion of the curve indicates the rapid adsorption of moisture on the surface of the substance.
2. Bound or Unbound Moisture: Bound moisture, also known as unbound moisture, refers to moisture that is held within the molecular structure of the substance and requires more energy to remove, such as heat during drying processes. On an equilibrium moisture curve, the region representing bound or unbound moisture would typically be the later portion of the curve where there is a gradual increase in moisture content with increasing humidity or moisture concentration. This portion of the curve indicates the saturation of the substance with moisture, where additional moisture is being absorbed into the internal structure of the substance.

In summary, the initial steep portion of the equilibrium moisture curve typically represents free moisture, while the later gradual portion represents bound or unbound moisture. However, the precise appearance of these regions on the curve would depend on the specific properties of the substance and the conditions of the equilibrium moisture experiment.