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Q1. The standard enthalpy of formation of NH3 is - 46 .0kj mol-1. If  the enthalpy of formation of H2 rom its atoms is - 436 kj mol-1 and that of N2 is -712 kj mol-1, the average bond enthalpy of N - H bond in NH3 is

(a) - 964 kj mol-1

(b) +352 kj mol-1

(c) + 1056 kj mol-1

(d) - 1102 kj mol-1

Q2. The time for half life period of a certain reaction A` ->` products is 1 hour. When the initial concentration of the reactant 'A' is 2.0 mol-1 how much time does it take for its concentration to from 0.50 to 0.25 mol L-1 if it is a zero order reaction?

Q3. A solution containing 2.675g of CoCI3. 6NH3 (molar mass=267.5g mol-1)is passed through a cation exchanger. The chloride ions obtained in solution were treated with excess of AgNO3 give 4.78g of AgCI (molar mass = 143.5g mol-1). The formula of the complex is (At. mass of Ag = 108 u)

Q4. Consider the reaction: CI2 (aq)  + H2S(aq) S(s) + 2H+(aq) +2CI-(aq) The rate equation for this reaction is rate = k [CI2][H2S] Which of these mechanisms is/are consistent with this rate equation? A. CI2 + H2S`->` H+ + CI- + CI+ + HS - (slow) CI+ +HS- `->` H+ +

Q5. If 10-4 dm3 of water is introduced into a 1.0dm3 flask at 300 k, how many moles of water are in the vapour phase when equilibrium is established?(Given: Vapour pressure of H2O at 300k is 3170 Pa; R=8.314 jk-1 mol-1)

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