IIT JEE Practice Question and Answer

Q: Order of basicity of amines in gaseous state? 1289 0

  • 1
    2'> 1'> 3' > NH3
    Correct
    Wrong
  • 2
    3' > 2' > 1'> NH3
    Correct
    Wrong
  • 3
    1' > 2' > 3'> NH3
    Correct
    Wrong
  • 4
    2'> 3'> 1' > NH3
    Correct
    Wrong
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Answer : 2. "3' > 2' > 1'> NH3"
Explanation :

Answer: B) 3' > 2' > 1'> NH3 Explanation: The order of basicity in ammonia is different in gaseous phases vs. aqueous phases due to hydrogen bonding.   So in gaseous phases it's the well known: 3' > 2' > 1'> NH3. Just so we're on the same page, this is due to the inductive effect of electron donating alkyl groups--they destabilize the lone pair on nitrogen atom, making nitrogen more basic.   But in aqueous phase, the order is slightly different: 2'> 1'> 3' > NH3.

Q: Negative plus a positive equals 1288 0

  • 1
    negative
    Correct
    Wrong
  • 2
    positive
    Correct
    Wrong
  • 3
    zero
    Correct
    Wrong
  • 4
    Can't be determined
    Correct
    Wrong
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Answer : 4. "Can't be determined"
Explanation :

Answer: D) Can't be determined Explanation: We know that a negative value plus a positive value always count backward and the sign depends on the bigger value sign. When you are adding a negative number to a positive number, then the value counts backward and takes the sign of the biggest number.   For example:: Adding -5 and +2 -5 + 2 = -3 (big number is 5 and its sign is '-')   Adding -3 and  +5 +5 + (-3) = 5 - 3 = +2(big number is 5 and it has sign '+').

Q: A Tank is normally filled in 9 hours but takes four hours longer to fill because of a leak in its bottom. If the tank is full, the leak will empty it in ? 1288 0

  • 1
    32.5 hrs
    Correct
    Wrong
  • 2
    29.25 hrs
    Correct
    Wrong
  • 3
    30.30 hrs
    Correct
    Wrong
  • 4
    31 hrs
    Correct
    Wrong
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Answer : 2. "29.25 hrs"
Explanation :

Answer: B) 29.25 hrs Explanation: Let the leak will empty the tank in x hrs  Then, 1/9 - 1/x = 1/13 x = 29.25 hrs

Q: You drive to the store at 20 kmph and return by the same route at 30 kmph. Discounting the time spent at the store, what was your average speed ? 1287 0

  • 1
    25 kmph
    Correct
    Wrong
  • 2
    24 kmph
    Correct
    Wrong
  • 3
    26 kmph
    Correct
    Wrong
  • 4
    22 kmph
    Correct
    Wrong
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Answer : 2. "24 kmph"
Explanation :

Answer: B) 24 kmph Explanation: Average speed=total distance/total timeLet distance to store be  Kthen, total time =(K/20)+(K/30)=K/12and, total time =(2K)so average speed= 2K / (K/12) = 24kmph.

Q: 3 : 12 :: 5 : ? 1287 0

  • 1
    17
    Correct
    Wrong
  • 2
    30
    Correct
    Wrong
  • 3
    26
    Correct
    Wrong
  • 4
    32
    Correct
    Wrong
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Answer : 2. "30"
Explanation :

Answer: B) 30 Explanation: 332 + 3 = 12552 + 5 = 30

Q: A certain amount is divided among P, Q and R in the ratio of 3 : 7 : 6 respectively. If the difference between share of P and Q is Rs. 2700, what is R's share? 1287 0

  • 1
    Rs. 4050
    Correct
    Wrong
  • 2
    Rs. 2121
    Correct
    Wrong
  • 3
    Rs. 5040
    Correct
    Wrong
  • 4
    Rs. 3550
    Correct
    Wrong
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Answer : 1. "Rs. 4050"
Explanation :

Answer: A) Rs. 4050 Explanation: Let the ratio amount be 'p' 7p - 3p = 2700 4p = 2700 p = 675 R's Share = 675 × 6 = Rs. 4050

Q: Proclamation of Emergency under Article 352 has been done How many times ? 1286 0

  • 1
    4
    Correct
    Wrong
  • 2
    3
    Correct
    Wrong
  • 3
    2
    Correct
    Wrong
  • 4
    1
    Correct
    Wrong
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Answer : 2. "3"
Explanation :

Answer: B) 3 Explanation:

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Answer : 2. "17"
Explanation :

Answer: B) 17 Explanation: Since floor starts form the 1 therefore 2 will be the 1st floor.Form 1 to 10 only 4,6,8,9,10 are not prime.Form 11 to 20 only 14 ,16,18 are not prime also non of their digits are prime.From 21 to 30 each number has a prime number so it must no be consider.In between 40 to 49 we have to consider only 40,44,46,48,49.50 to 59 follow either of the condition so we have too neglect it.In between 60 to 68 60,64,66,68.total option = 17.

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