Question

Which of the following processes have a ΔS > 0? Which of the following processes have a > 0? 2HCl(g) → H2(g) + Cl2(l) cesium chloride dissolves in pure water lithium fluoride forms from its elements 2NH3(g) + CO2(g) → NH2CONH2(aq) + H2O(l) All of the above processes have a ΔS > 0.

Answer 1

Answer: b) cesium chloride dissolves in pure water

Step-by-step explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

`\Delta S` is positive when randomness increases and
`\Delta S` is negative when randomness decreases.

a)
`2HCl(g)\rightarrow H_2(g)+Cl_2(l)`

As one mole of the gas is converted to liquid, the randomness of particles decreases and hence
`\Delta S` is negative and
`\Delta S<0`.

b) cesium chloride dissolves in pure water:

As solid is converted to aqueous state and ions are formed, the randomness of particles increases and hence
`\Delta S` is positive and
`\Delta S>0`

c) lithium fluoride forms from its elements :

As molecules combine to form a single product, the randomness of particles decreases and hence
`\Delta S` is negative and
`\Delta S<0`

d)
`2NH_3(g)+CO_2(g)\rightarrow NH_2CONH_2(aq)+H_2O(l)`

As gas is converted to liquid, the randomness of particles decreases and hence
`\Delta S` is negative and
`\Delta S<0`