For a given isotherm for one mole of an ideal gas which follows boyle's law what will be the value of temperature
Answers
As other people have pointed out, Boyle's law shows an inverse relationship between pressure and volume. If you graph P = 1/V (the most basic form of an inverse relationship) then you will get a falling curve rather than an straight line.
Although this is true, depending on how intuitive you find math, it isn't always satisfying. A different way of thinking about it is in terms of the extremes. We know that no matter how great the pressure, the volume should never be negative (what would that even mean?). We also no that without any pressure, there is no reason for the gas to stop expanding.
In a mathematical context, this means that the pressure intercept (V = 0) needs to be infinite - the only way to compress all the space out of a gas is with infinite pressure. Similarly, we know that the volume intercept (P = 0) also needs to be infinite - the gas should never stop expanding if there is not pressure.
If you try sketching this on a graph you will quickly find that the only way for this to work is if it is a falling curve, hence the shape of Boyle's law curve.