Multiple Choice QuestionsThe standard enthalpy of formation of NH3 is– 46.0 kJmol–1. If the enthalpy of formation of H2 from its atoms is – 436 kJ mol–1 and that of N2 is – 712 kJ mol–1,the average bond enthalpy of N – H bond is NH3 is
-964 kJ mol-1
+352 kJ mol-1
+1056 kJ mol-1
+1056 kJ mol-1
The energy required to break one mole of Cl— Cl bonds in Cl2 is 242 kJ mol–. The longest wavelength of light capable of breaking a single Cl — Cl bond is
(c= 3 x 108 ms–1and NA = 6.02 x 1023 mol–1)
594 nm
640 nm
700 nm
700 nm
The solubility product of silver bromide is 5.0 x 10-13. The quantity of potassium bromide (molar mass taken as 120 g mol–1)to be added to 1 litre of 0.05 M solution of silver nitrate to start the precipitation of AgBr is
1.2 x 10-10 gÂ
1.2 x 10-9 g
6.2 x 10-5 gÂ
6.2 x 10-5 gÂ
For a particular reversible reaction at temperature T, ΔH and ΔS were found to be both +ve. If Te is the temperature at equilibrium, the reaction would be spontaneous whenÂ
Te>T
T >Te
Te is 5 times T
Te is 5 times T
Given
C(grahite) + O2(g) → CO2(g)
ΔrH° = - 393.5 kJ mol-1
H2(g) + 1/2O2(g) → H2O (l)
ΔrH° = +890.3 kJ mol-1
Based on the above thermochemical equations, the value of ΔrH° at 298 K for the reaction
C(grahite) + 2H2(g) →CH4 will be
 +74.8 kJ mol–1Â
+144.0 kJ mol–1
–74.8 kJ mol–1
–74.8 kJ mol–1
In a fuel cell methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is
CH3OH(l) + 3/2O2(g) → CO2(g) + 2H2O(l)
At 298 K standard Gibb’s energies of formation for CH3OH(l), H2O(l) and CO2(g) are –166.2, –237.2 and –394.4 kJ mol–1 respectively. If
standard enthalpy of combustion of methanol is –726 kJ mol–1, efficiency of the fuel cell will be:
80%
97%
87%
87%
Which one of the following reactions of Xenon compounds is not feasible?
XeO3+ 6HF → XeF6 + 3H2O
3XeF4 +6H2O → Xe+XeO3+ 12HF+ 1.5O2
2XeF2 + 2H2O → 2Xe + 4HF +O2
2XeF2 + 2H2O → 2Xe + 4HF +O2
Oxidising power of chlorine in aqueous solution can be determined by the parameters indicated below
The energy involved in conversion of 
152 kJ mol-
-610Â kJ mol-
-850Â Â kJ mol-
-850Â Â kJ mol-
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