ANS:C - both (a) and (b)

Molar concentration, often denoted as 𝑐c or 𝐶C, represents the concentration of a substance in a solution and is defined as the amount of substance (usually expressed in moles) divided by the volume of the solution (usually expressed in liters). Mathematically, it is expressed as: 𝑐=𝑛𝑉c=Vn​ Where:

• 𝑐c is the molar concentration in units of moles per liter (mol/L or M).
• 𝑛n is the number of moles of the solute.
• 𝑉V is the volume of the solution in liters.

Molar concentration quantifies the amount of solute dissolved in a given volume of solvent. It is a crucial parameter in chemistry and plays a significant role in various chemical reactions and physical processes, including the entropy change of mixing. The entropy change of mixing two liquid substances depends on the molar concentration because it influences the randomness or disorder of the system. When two substances are mixed, the resulting entropy change is related to the degree of disorder introduced into the system. Higher molar concentrations typically result in greater disorder upon mixing, leading to higher entropy changes. In summary, molar concentration quantifies the amount of substance present in a solution per unit volume, and it affects the entropy change during the mixing process due to its influence on the disorder of the system.