A reaction occurs spontaneously if:
1. T∆S > ∆H and ∆H is +ve and ∆S are –ve
2. T∆S = ∆H and both ∆H and ∆S are +ve
3. T∆S < ∆H and both ∆H and ∆S are +ve
4. T∆S > ∆H and both ∆H and ∆S are +ve
The absolute enthalpy of neutralisation of the reaction: MgO(s) +2HCl(aq) → MgCl2(aq)+H2O(l) will be:
1. 57.33 kJ mol–1
2. –57.33 kJ mol–1
3. Greater than –57.33 kJ mol–1
4. Less than –57.33 kJ mol–1
Which of the following pairs of chemical reactions is certain to result in a spontaneous reaction:
1. Endothermic and decreasing disorder
2. Exothermic and increasing disorder
3. Endothermic and increasing disorder
4. Exothermic and decreasing disorder
Identify the correct statement regarding entropy:
1. | At absolute zero of temperature, the entropy of all crystalline substances is taken to be zero |
2. | At absolute zero of temperature, the entropy of a perfectly crystalline substance is +ve |
3. | At absolute zero of temperature, the entropy of a perfectly crystalline substance is taken to be zero |
4. | At 0 °C , the entropy of a perfectly crystalline substance is taken to be zero |
One mole of an ideal gas at 300 K is expanded isothermally from an initial volume of 1 litre to 10 litres. The ∆E for this process is:
(R = 2 cal. )
1. 1381.1 cal.
2. Zero
3. 163.7 cal.
4. 9 lit. atm
If the bond energies of H–H, Br – Br, and H –Br are 433, 192, and 364 kJ mol–1 respectively, the ∆Hº for the reaction H2(g) + Br2(g) → 2HBr(g) will be:
1. +103 kJ
2. +261kJ
3. –103 kJ
4. –261 kJ
Which of the following statements are true for a cyclic process?
a. | W = 0 | b. | ∆E = 0 |
c. | ∆H = 0 | d. | ∆E ≠ 0 |
1. a, b
2. b, c
3. c, d
4. a, d
If a system is expanded under adiabatic process, then:
1. Temperature increases
2. ∆E decreases
3. ∆E increases
4. None of the above
Which of the following is true for a reaction in which all the reactants & products are liquids:
1. ∆H = ∆E
2. ∆H = ∆W
3. ∆H > ∆E
4. None of the above
Considering entropy (S) as a thermodynamic parameter, the criterion for the spontaneity of any process is:
1.
2.
3.
4.