Gas to liquid and liquid to solid conversion is: 

The correct answer is condensation and solidification respectively.

Key Points

• Condensation: The process of gas transforming into a liquid state.
• Solidification: The process of liquid transforming into a solid state.
• Condensation usually occurs when gas cools down and loses energy.
• Solidification occurs when a liquid cools and its particles lose kinetic energy, forming a solid structure.
• Both processes are part of the phase transitions governed by temperature and pressure conditions.

Additional Information

• Phase Transition: The transformation from one state of matter (solid, liquid, gas) to another.
• Melting: The process where a solid turns into a liquid.
• Freezing: Another term for solidification, where a liquid turns into a solid.
• Vaporization: The process where a liquid turns into a gas, including boiling and evaporation.
• Sublimation: The process where a solid directly transitions into a gas without becoming a liquid first.