Question

In which of the following processes does the entropy decrease?

• A. Conversion of oxygen to ozone
• B. Conversion of dry ice to $C{O}_2\left(g\right)$
• C. Thermal decomposition of sodium bicarbonate
• D. Desorption of $H_2\left(g\right)$ from nickel surface

Answer 1

The correct option is A Conversion of oxygen to ozone

Entropy is a state function which measures the randomness or state of disorder in a process.
Entropy increases when its particles have more freedom of motion. Thus entropy increases when you have more moles of gaseous products than reactant particles.
So, when a gas is released, the entropy increases as in option (d).
But in option (a) number of moles of reactant is greater than the moles of the products so the entropy decreases