Q1: Real gases approach ideal behaviour at

ANS:B - low pressure & high temperature.

Real gases tend to behave more like ideal gases under conditions where the individual gas particles are far apart from each other, leading to fewer intermolecular interactions. This typically occurs at high temperatures and low pressures. At high temperatures, gas particles possess higher kinetic energies, which overcome intermolecular forces, resulting in greater separation between particles. At low pressures, the distance between gas particles is increased, reducing the likelihood of intermolecular interactions. So, the statement "low pressure & high temperature" describes the conditions under which real gases approach ideal behavior. Therefore, the correct answer is "low pressure & high temperature."