The change in the standard Gibbs free energy (ΔGº) for the dissociation of nitrous acid (HNO2) at 298 K is 19.09 kJ. If the pH of the solution after equilibrium is reached is 1.30 and the NO2 – concentration at equilibrium is 0.00060 M. What is the equilibrium concentration of HNO2? Hint: Use pH to determine the equilibrium concentration of H+ .
HNO2(aq) H + (aq) + NO2 – (aq)
Answer: Option (B) is the correct answer.
Explanation:
Degree of randomness of the molecules of a substance is known as entropy. More is the kinetic energy between the molecules of a substance more will be the degree of randomness.
Therefore, when a substance is present in a gaseous state then it has the maximum entropy. In liquid state, molecules are closer to each other so, there is less randomness between them.
On the other hand, in solid state molecules are much more closer to each other as they arr held by strong intermolecular forces of attraction. Therefore, they have very less entropy.
- When liquid water is formed from gaseous hydrogen and oxygen molecules then gas is changing into liquid. So, there is decrease in entropy.
- When
decomposes then the reaction will be as follows.
Since, 1 mole is producing 2 moles. This means that degree of randomness is increasing as both the molecules are present in gaseous form.
- In formation of a precipitate, aqueous solution is changing into solid state. Hence, degree of randomness is decreasing.
- Rusting of iron also leads to the formation of solid as it forms
.
Thus, we can conclude that decomposition of
gas to
gas is the process that is expected to have an increase in entropy.
Talking about ions, a cation has a positive charge. That means a positive charge is gained by an atom that gives out electrons.
Scatter Plots. Scatter Plots show the relationship between two variables.