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Carbon dioxide unusual because it has n...

Carbon dioxide unusual because it has no liquid phase at normal atmospheric pressure. Instead, the solid sublimes directly to the gas phase. To obtain the liquid phase at room temperature, a pressuer of _____`MP` a must be applied.

Text Solution

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It is possible to change a gas into a liquid or a liquid into a gas by a process such that there is always a single phase present.

e.g., In figure given above, we can move from A to vetically by increasing the temperature, then we can reach the point by compressing the gas at constant temperature along the isotherm (isotherm at `31.1^(@) C`). The pressure will increase.
Now, we can move vertically down towards D by lowering the temperature. As soon as we cross the point H on the critical isotherm, we get liquid. Thus, at no stage during the process, we can through two - phase region.
It process is carried out at the critical temperature, substance always remains in one phase. This is called continuity of state between the gaseous and the liquid state.
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