Q1: Which of the following is not used for computing latent heat of vaporisation ?

ANS:D - Hess's law of constant heat summation

Hess's law of constant heat summation is not used for computing the latent heat of vaporization. Hess's Law deals with the principle that the total enthalpy change during a chemical reaction is independent of the route by which the reaction takes place, as long as the initial and final conditions are the same. It is primarily applied to calculate the enthalpy change in chemical reactions based on known enthalpies of formation or other enthalpy changes. On the other hand, the Clausius-Clapeyron equation, Reference substance plots based on Dühring & Othmer plots, and Kistyakowsky's equation are commonly used methods for computing the latent heat of vaporization. These methods are based on thermodynamic principles and empirical data to determine the latent heat of vaporization for a given substance.