Option 1 : Positive slope

ST 1: Reasoning & Mental Ability

6964

15 Questions
15 Marks
15 Mins

**Explanation:**

Mollier diagram is h-s diagram of pure substance.

- As the pressure increases, the saturation temperature increases, and so the slope of the
**isobar also increases**. Hence, the constant pressure lines diverge from one another. - The critical isobar is a tangent at the critical point.
- Although the slope of an isobar remains continuous beyond the saturated vapour line, the isotherm bends towards the right and its slope decreases asymptotically to zero, because in the idea gas region it becomes horizontal and the constant enthalpy implies constant temperature.