All India Engineering / Architecture Entrance Examination (AIEEE)

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AIEEE 2009 Chemistry

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)

Q. 5. On the basis of the following thermochemical data:

1. -343.52 kJ
   
   
2. -22.88 kJ
   
   
3. -228.88 kJ
   
   
4. +228.88 kJ

Q. 6. The half life period of a first order chemical reaction is 6.93 minutes. The time required for the completion of 99% of the chemical reaction will be (log 2 = 0.301):

1. 460.6 minutes
   
   
2. 230.3 minutes
   
   
3. 23.03 minutes
   
   
4. 46.06 minutes

Sol:
  

Answer : (4)

Q. 7. Copper crystallises in fcc with a unit cell length of 361 pm. What is the radius of copper atom?

1. 181 pm
   
   
2. 108 pm
   
   
3. 127 pm
   
   
4. 157 pm

Sol:

Answer : (3)

Q. 8. Given The value of standard electrode potential for the change,

1. -0.270 V
   
   
2. –0.072 V
   
   
3. (3) 0.385 V
   
   
4. (4) 0.770 V

Sol:

Answer : (4)