Question

what is isothermal irreversible change

Answer 1

First you should understand the meaning of each term. Here Isothermal means the change is taking place at constant temperature and Reversible Process (in thermodynamics) means the process in which the system and surrounding can be restored to initial states from final state . The system remains almost in a state of equilibrium with the surrounding at every stage of process is known as reversible process. For a process to be reversible, change must be carried out infinitesimally slowly. In reversible process, driving force and opposing forces are nearly same.
Isothermal reversible change means the reversible process is carried out at constant temperature.