19.

In terms of Charles’s law explain why –273°C is the lowest possible temperature.

The law states that at constant pressure, the volume of a fixed mass of gas is directly proportional to its absolute temperature. It was found that for all gases (at any given pressure), the plots of volume vs. temperature is a straight line. If this line is extended to zero volume, then it intersects the temperature axis at -273⁰C.

In other words, the volume of any gas at 273 ⁰C is zero. This is because all gases get liquefied before reaching a temperature of 273⁰C.

Hence, it can be concluded that -273 ⁰C is the lowest possible temperature