Question

In which of the following process entropy increases?

a) Rusting of iron

b) Vapourisation of Camphor

c) Crystallisation of sugar from syrup

d) Atomisation of dihydrogen

• A. a and b
• B. b and c
• C. b and d
• D. Only d

Answer 1

The correct option is C b and d

In vapourisation of camphor, we go from solid to gaseous state therefore randomness increases and entropy increases.
$H_2\left(g\right)\to 2H\left(g\right)$
No. of gaseous substances increase Therefore entropy increases.
$C_6{H}_{12}{O}_6\left(l\right)\to C_6{H}_{12}{O}_6\left(s\right)$
While going from liquid to solid entropy decreases

In rusting of iron, gaseous oxygen combines to form solid rust. In that case also entropy decreases.