Question
In the vicinity of the triple point, the equation of liquid-vapour boundary in the 𝑷 − 𝑻 phase diagram for ammonia is 𝐥𝐧 𝑷 = 𝟐𝟒. 𝟑𝟖 − 𝟑𝟎𝟔𝟑/𝑻, where P is pressure (in Pa) and 𝑻 is temperature (in K). Similarly, the solid-vapour boundary is given by 𝐥𝐧 𝑷 = 𝟐𝟕. 𝟗𝟐 − 𝟑𝟕𝟓𝟒/𝑻. The temperature at the triple point is ___________ K (round off to one decimal place).
Answer :
Correct answer is : 195.19
At triple point temperature of solid, liquid and vapour is same
∴ Equating
Now,
Multiplying by ‘T’ on both sides
24.38 T – 3063 = 27.92 T – 3754
3.54 T = 691
T = 195.197 K
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