Question

In the vicinity of the triple point, the vapour pressures of liquid and solid ammonia are respectively given by

$lnP=15.16-3063/T\text{and}lnP=18.70-3754T$

where P is in atmospheric and T is in kelvin. What is the
temperature at the triple point?

• A. 195.2

Answer 1

The correct option is A 195.2
At triple point all the three phases exist in equilibrium.

$\therefore$ Triple point pressure of liquid and solid ammonia is same

$\therefore$ $15.16-\frac{3063}{T}=18.70-\frac{3754}{T}$

$\left(15.16\right)T-3063=\left(18.70\right)T-3754$

$\left(3.54\right)T=691$

$\text{or}T=195.2K$