Question

In which of the following processes entropy increases? 

A. A liquid evaporates to vapour. 

B. Temperature of a crystalline solid lowered from 130 K to 0 K.

C. \(2NaHCO_{3(s)} \rightarrow Na_2CO_{3(s)} + CO_{2(g)} + H_2O_{(g) }\)

D. \(Cl_{2(g)} \rightarrow 2Cl_{(g) }\)

Choose the correct answer from the options given below: 

(1) A and C 

(2) A, B and D 

(3) A, C and D 

(4) C and D

Answer 1

Correct option is (3) A, C and D 

When a liquid evaporates to vapour entropy increases.

\(2NaHCO_{3(s) } \rightarrow Na_2CO_{3(s)} + CO_{2(g) }+ H_2O_{(g)}\)

Number of gaseous product molecules increases so entropy increases.

\(Cl_{(2g)} \rightarrow 2Cl _{(g)}\)

1 mole \(Cl_{2(g)}\) form 2 mol \(Cl_{(g)}\). So entropy increases.