What is critical temperature? Can a gas be liquefied at any temperature by increasing its pressure?

Explanation

### Step-by-Step Solution

**Step 1: Define Critical Temperature**
- Critical temperature (Tc) is the maximum temperature at which a gas can be converted into a liquid by applying pressure. Above this temperature, no amount of pressure will cause the gas to liquefy.

**Step 2: Understand the Conditions for Liquefaction**
- To liquefy a gas, two conditions must be met:
1. The temperature of the gas must be reduced.
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