Predict in which of the following, entropy decreases

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

$2 N a H C O_{3} (s) \to N a_{2} C O_{3} (s) + C O_{2} (g) + H_{2} O (g)$

$H_{2} (g) \to 2 H (g)$

Temperature of a crystalline solid is raised from 0 K to 115 K.

A liquid crystallizes into a solid.

answer is A.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

(1) After freezing, the molecules attain an ordered state and therefore, entropy decreases.

(2) At 0 K, the constituent particles are static and entropy is minimum. If temperature is raised to 115K. these begin to move and oscillate about their equilibrium positions in the lattice and system becomes more disordered. Therefore entropy increases
(3) Reactant. $N a H C O_{3}$ is a solid and it has low entropy. Among products there are one solid and two gases. Therefore, the products represent a condition of higher entropy
(4) Here one molecule gives two atoms i.e.. number of particles increase leading to more disordered state. Two moles of H atoms have higher entropy than one mole of dihydrogen molecule.

Watch 3-min video & get full concept clarity