IIT JEE Practice Question and Answer
8Q: Order of basicity of amines in gaseous state? 1289 05b5cc67ee4d2b4197774c274
5b5cc67ee4d2b4197774c274- 12'> 1'> 3' > NH3false
- 23' > 2' > 1'> NH3true
- 31' > 2' > 3'> NH3false
- 42'> 3'> 1' > NH3false
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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 05b5cc6a1e4d2b4197774cac7
5b5cc6a1e4d2b4197774cac7- 1negativefalse
- 2positivefalse
- 3zerofalse
- 4Can't be determinedtrue
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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 05b5cc6d4e4d2b4197774e5b1
5b5cc6d4e4d2b4197774e5b1- 132.5 hrsfalse
- 229.25 hrstrue
- 330.30 hrsfalse
- 431 hrsfalse
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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 05b5cc745e4d2b4197774fa4a
5b5cc745e4d2b4197774fa4a- 125 kmphfalse
- 224 kmphtrue
- 326 kmphfalse
- 422 kmphfalse
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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 05b5cc6b9e4d2b4197774d702
5b5cc6b9e4d2b4197774d702- 117false
- 230true
- 326false
- 432false
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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 05b5cc6bfe4d2b4197774d9ec
5b5cc6bfe4d2b4197774d9ec- 1Rs. 4050true
- 2Rs. 2121false
- 3Rs. 5040false
- 4Rs. 3550false
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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 05b5cc6cae4d2b4197774e077
5b5cc6cae4d2b4197774e077- 14false
- 23true
- 32false
- 41false
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Answer : 2. "3"
Explanation :
Answer: B) 3 Explanation:
Q: Maheshwari wants to buy 7 floors in an 68 storied building whose numbering stars from 1 upto 68. But she has to follow certain rules which are as follows : 1) None of the floor should be a prime number 2) None of the digit of the floor should be a prime number 3) Maheshwari cannot buy the 1st floor as it is being assigned to the architect. So how many options are left with Maheshwari to buy the floors ? 1286 05b5cc709e4d2b4197774f2a8
5b5cc709e4d2b4197774f2a8- 111false
- 217true
- 313false
- 419false
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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.

