Q. No.Select the correct option based on statements given below:
Assertion (A):
Combustion of all organic compounds is an exothermic reaction.
Reason (R):
The enthalpies of all elements in their standard state are zero.
1.
Both (A) and (R) are True and (R) is the correct explanation of (A).
2.
Both (A) and (R) are True but (R) is not the correct explanation of (A).
3.
(A) is True but (R) is False.
4.
(A) is False but (R) is True.
| Assertion (A): | Spontaneous process is an irreversible process and may be reversed by some external agency. |
| Reason (R): | A decrease in enthalpy is a contributing factor to spontaneity. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
| Assertion (A): | A liquid crystallizes into a solid and is accompanied by a decrease in entropy. |
| Reason (R): | In crystals, molecules organize in an ordered manner. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
Thermodynamics is not concerned about which of the following?
| 1. | Energy changes involved in a chemical reaction. |
| 2. | The extent to which a chemical reaction proceeds. |
| 3. | The rate at which a reaction proceeds. |
| 4. | The feasibility of a chemical reaction. |
Which among the following statements about open, closed, and isolated systems is correct?
| 1. | The presence of reacting species in a covered beaker represents an open system. |
| 2. | In a closed system, there is an exchange of both energy and matter between the system and its surroundings. |
| 3. | A system containing reactants in a closed vessel made of copper is an example of a closed system. |
| 4. | A system containing reactants in a thermos flask or any other closed, insulated vessel is an example of a closed system. |
What happens to the specific heat of a gas when its volume is reduced to half of its initial value?
| 1. | Reduce to half | 2. | Be Doubled |
| 3. | Remain constant | 4. | Increase four times |
During the complete combustion of one mole of butane, 2658 kJ of heat is released. The thermochemical reaction for this change is:
| 1. | |
| 2. | |
| 3. | |
| 4. |
Find the value of the standard enthalpy of formation (ΔfH°).
1. Zero
2. Less than ΔfU°
3. Greater than ΔfU°
4. Equal to ΔfU°
Calculate the correct values of heat transfer (q), change in temperature (ΔT), and work done (W) for the free expansion of an ideal gas under adiabatic conditions.
1. q = 0, ΔT ≠ 0, W = 0
2. q ≠ 0, ΔT = 0, W = 0
3. q = 0, ΔT = 0, W = 0
4. q = 0, ΔT = 0, W ≠ 0
The pressure-volume work for an ideal gas can be calculated by using the expression .
The work can also be calculated from the pV-plot by using the area under the curve within the specified limits.
An ideal gas is compressed (a) reversibly or (b) irreversibly from volume to .
The correct option is:
| 1. | \( \mathrm{W} \text { (reversible) }=\mathrm{W} \text { (irreversible) }\) |
| 2. | \( \mathrm{W} \text { (reversible) }<\mathrm{W} \text { (irreversible) }\) |
| 3. | \( \mathrm{W} \text { (reversible) }>\mathrm{W} \text { (irreversible) }\) |
| 4. | \( \mathrm{W} \text { (reversible) }=\mathrm{W} \text { (irreversible) } + \text P_{\text {ext}}.\Delta V\) |
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