Q36 · CSIR NET Chemistry, December 2014
Paper: CSIR NET December 2014 · Subject: Physical Chemistry · Chapter: Thermodynamics · Topic: Laws State Functions · Marks: 2 · Difficulty: Easy
The exact differential $d f$ of a state function $f(x, y)$, among the following is
(a)$x d y$
(b)$d x-\frac{x}{y} d y$
(c)$y d x-x d y$
(d)$\frac{1}{y} d x-\frac{x}{y^{2}} d y$
Answer
Answer: D ✓ checked by 4AB · confidence high
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
(1/y)dx − (x/y²)dy = d(x/y). The cross derivatives ∂(1/y)/∂y = −1/y² and ∂(−x/y²)/∂x = −1/y² are equal (d).
Study loop for Thermodynamics