The correct answer is Viscosity increases.. Key Points • The viscosity of gases increases with an increase in temperature. This phenomenon is due to the molecular behavior of gases. • When temperature rises, the kinetic energy of gas molecules increases. Molecules move faster, causing more frequent collisions, which results in higher viscosity. • Unlike liquids, where viscosity decreases with temperature, gases behave differently due to the nature of intermolecular forces and molecular motion. Hence, the statement is correct. • The increased molecular collisions in gases lead to an enhanced transfer of momentum between layers of gas, which directly relates to the increase in viscosity. • In gases, the viscosity depends on the mean free path and speed of molecules, both of which increase with temperature. Thus, the effect of temperature on gas viscosity is opposite to that of liquids. • Hence, the correct answer is Viscosity increases. Additional Information • Viscosity: • Viscosity is the measure of a fluid's resistance to deformation or flow. It depends on molecular interactions and external conditions like temperature and pressure. • For gases, viscosity is primarily determined by the motion and collision of molecules, rather than intermolecular attractions, which dominate in liquids. • Temperature Effect on Gases: • As the temperature of a gas increases, the molecules move faster, increasing their kinetic energy. • Higher kinetic energy results in more frequent collisions and greater momentum transfer between layers, leading to increased viscosity. • Example: The viscosity of air increases as it is heated, which is why calculations for industrial gas flow systems consider temperature effects. • Comparison with Liquids: • In liquids, viscosity decreases with temperature because the intermolecular forces weaken as molecules gain energy. • For gases, the opposite occurs because viscosity depends on the molecular motion rather than intermolecular forces. Important Points • Application of Viscosity in Gases: • Industrial Processes: Viscosity is crucial in designing systems for gas flow, such as pipelines, engines, and compressors. • The viscosity of gases at different temperatures is a critical parameter in aerodynamics and combustion engineering. • Scientific Explanation: • Maxwell's Theory: James Clerk Maxwell explained the relationship between temperature and gas viscosity using kinetic theory. • Mathematical Relation: Gas viscosity increases proportionally to the square root of absolute temperature.