Q1: Surface renewal model of mass transfer was enunciated by

ANS:C - Danckwerts

The surface renewal model of mass transfer was enunciated by Toor and Marchello. The surface renewal theory, proposed by Toor and Marchello in 1965, is a model used to describe mass transfer at fluid-solid interfaces. It extends the concepts of the film theory and takes into account the dynamic nature of the interface, where the solid surface is intermittently exposed to fresh fluid. According to the surface renewal theory, the mass transfer rate is influenced not only by the concentration gradient at the interface but also by the frequency and duration of the contact between the fresh fluid and the solid surface. This dynamic behavior of the interface results in periodic fluctuations in the concentration profile near the surface, leading to enhanced mass transfer rates compared to the steady-state film theory. The surface renewal theory has found applications in various fields, including chemical engineering, environmental engineering, and biotechnology, where accurate prediction of mass transfer rates at fluid-solid interfaces is essential for process design and optimization. Therefore, the correct answer is Toor and Marchello.