Question

The volume-temperature graph of a given mass of an ideal gas at constant pressure is shown in the given figure. Which graph (out of $1,2$ or $3$) will correspond to the highest pressure?

Answer 1

We know that the ideal gas equation is $PV=nRT$
For a given mass of a gas, $n$ and $R$ are constant.
Hence, $PV\propto T$
At a particular temperature, volume is inversely proportional to pressure, i.e., $V\propto \frac{1}{P}$.
Hence, the highest pressure will correspond to the one with lowest volume.
As it can be seen from the graph that the lowest volume and hence, corresponding to highest pressure is represented by graph $1$.