All India Engineering / Architecture Entrance Examination (AIEEE)

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AIEEE 2009 Chemistry

Q. 1. Arrange the carbanions , in order of their decreasing stability:

Sol:

Answer : (4)

Q. 2. In Cannizzaro reaction given below

1. the deprotonation of PhCH₂OH
2. the attack of at the carboxyl group
   
   
3. the transfer of hydride of the carbonyl group
   
   
4. the abstraction of proton from the carboxylic group

Sol.: Cannizzaro reaction involves hydride transfer as the rate limiting step.

Answer : (3)

Q. 3. Two liquids X and Y form an ideal solution. At 300 K, vapour pressure of the solution containing 1 mol of X and 3 mol of Y is 550 mmHg. At the same temperature, if 1 mol of Y is further added to this solution, vapour pressure of the solution increases by 10 mmHg. Vapour pressure (in mmHg) of X and Y in their pure states will be, respectively:

1. 500 and 600
   
   
2. 200 and 300
   
   
3. 300 and 400
   
   
4. 400 and 600

Sol:

Answer : (4)

Q. 4. In a fuel cell, methanol is used as fuel and oxygen gas is used as an oxidizer. The reaction is; 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

1. 97%
   
   
2. 80%
   
   
3. 87%
   
   
4. 90%

Sol:
 
Answer : (1)