The correct option is (a).
Explanation
The physical state of matter is governed by temperature and pressure. Altering these conditions changes the kinetic energy of particles and the distance between them, leading to phase transitions such as liquefaction or sublimation.Statement 1 is Correct: Gases can be liquefied by applying high pressure and reducing the temperature. High pressure compresses the gas molecules, bringing them closer together, while low temperature reduces their kinetic energy. This combination allows intermolecular forces to hold the particles together in a liquid state.
Statement 2 is Incorrect: Solid Carbon Dioxide (Dry Ice) is stored under high pressure. If the pressure is low, it tends to sublime rapidly. Therefore, high pressure is maintained to preserve its solid state.
Statement 3 is Incorrect: When pressure is decreased to 1 atmosphere, Solid Carbon Dioxide converts directly into the gaseous state, not the liquid state. This process is called sublimation. Because it transitions directly to gas without leaving a liquid residue, it is referred to as "dry ice."
Key Takeaway: Liquefaction of gases requires high pressure and low temperature. Solid Carbon Dioxide (Dry Ice) undergoes sublimation (solid to gas) at 1 atmosphere pressure and must be stored under high pressure.