Final answer:
A real gas deviates most from ideal behavior under the conditions of strong interparticle attractions, low temperature, and high pressure.
Step-by-step explanation:
A real gas deviates most from ideal behavior under the following set of conditions: strong interparticle attractions, low temperature, high pressure.
When a real gas has strong interparticle attractions, the gas particles are more likely to stick together and deviate from ideal behavior. Low temperature also contributes to the deviation as it slows down the gas particles and makes the attractive forces between them more prominent. High pressure further increases the deviation due to the decrease in empty space between the particles.
In summary, a real gas deviates most from ideal behavior when it has strong interparticle attractions, low temperature, and high pressure.