# Variation of Boiling point with pressure from Clausius-Clapeyron equation

For a first-order phase transition such as water to steam , we write Clausius-Clapeyron equation as:

$$\frac{dP}{dT}= \frac{L}{T \Delta V}$$

Now what I infer from this equation is that if the phase-transition takes place at a lower T (that is boiling point is lower) then the rate on the Left Hand Side increases which basically means that at that temperature any small change in T will cause high change in P. This inference is unsatisfactory to me and as such I want to understand what information this equation essentially gives.

More specifically, I wanted to understand a statement I had come across which said that this equation explains why boiling point of a liquid increases with increases in pressure. Although, physically I understand why this is true but how is this fact deduced from looking at the Clausius-Clapeyron equation?

I tried varying "stuff" in this equation to check whether I could get some sort of understanding but I just couldn't deduce that from this equation.

• Is the right side of that equation positive or negative? If it’s positive a positive change in P must be accompanied by a positive change in T. If the right hand side is negative, the reverse would be true. – Andrew Jan 6 at 22:44
• If the right side is positive, change in P accompanies a change in T. Right, but then is this T the boiling point? What happens to the right hand side T then? – Lost Jan 7 at 4:34
• The correct name is the Clausius-Clapeyron equation. – Poutnik Jan 13 at 8:39
• What exactly is LHS ? Left Hand Side ( of the equation ) ? Remember that saved words are often figuratively expensively paid by clarifications. LHS is not a common abbreviation. – Poutnik Jan 13 at 9:03
• @Poutnik Ok got it. Also, do you have something to contribute towards answering my question? – Lost Jan 13 at 9:17