Spontaneity

Q. For the reaction $2O_3\left(g\right)\to 3O_2\left(g\right),△H$ is negative, $△S$ and $△G$ are respectively:

1. +ve, +ve
2. +ve, -ve
3. -ve, +ve
4. -ve, - ve

Q. When disorderness of a system increases, the change is said to be:

1. Exothermic
2. Non-spontaneous
3. Endothermic
4. Spontaneous

Q. Which of the following processes is spontaneous?

1. Flow of heat from a colder to a hotter body
2. Boiling of water
3. Evaporation of water at room temperature
4. All of these

Q. Which of following is a non spontaneous process?

1. Rusting of iron
2. Boiling of water
3. Diffusion
4. Melting of ice

Q. The total entropy change $\left(△S_{total}\right)$ for the system and the surrounding of a spontaneous process is given by:

1. $△S_{total}=△S_{system}+△S_{surr}>0$
2. $△S_{total}=△S_{system}-△S_{surr}>0$
3. $△S_{system}=△S_{total}+△S_{surr}>0$
4. $△S_{surr}=△S_{total}-△S_{system}<0$

Q. The spontaneous flow of heat is always:

1. From low to high pressure
2. From high to low pressure
3. Unidirectional from low temperature to high temperature
4. Unidirectional from high temperature to low temperature

Q. Metallic mercury is obtained by roasting mercury (II) sulphide in a limited amount of air. Estimate the temperature range in which the standard reaction is product - favoured.
$HgS\left(s\right)+O_2\left(g\right)\to Hg\left(l\right)+S{O}_2\left(g\right)$
$△H^o=-238.6kJ/moleand△S^o=+36.7J/mole\cdot K$

1. When $T>200K$
2. When $T>300K$
3. At all temperatures
4. None of these

Q. The enthalpy change for a given reaction at 298 K is $-xJmo{l}^{-1}$ (x being positive). If the reaction occurs spontaneously at 298 K, the entropy change at that temperature

1. can be negative but numerically larger than $\frac{x}{298}$
2. can be negative but numerically smaller than $\frac{x}{298}$
3. cannot be negative
4. cannot be positive