IIT JEE Practice Question and Answer

Q: Which of the following is the strongest acid? 1339 0

  • 1
    ClCH2COOH
    Correct
    Wrong
  • 2
    BrCH2COOH
    Correct
    Wrong
  • 3
    FCH2COOH
    Correct
    Wrong
  • 4
    ICH2COOH
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 3. "FCH2COOH"
Explanation :

Answer: C) FCH2COOH Explanation: FCH2COOH is the strongest acid out of all .Since the electron withdrawing inductive effect (-I effect) of the halogens decreases in the order   F>Cl> Br> I , therefore the acidic strength of the α- halo acids decreases in the same order.   FCH2COOH  >  ClCH2COOH   >   BrCH2COOH   >   ICH2COOH.

Q: The average of marks in 3 subjects is 224. The first subject marks is twice the second and the second subject marks is twice the third. Find the second subject marks ? 1337 0

  • 1
    384
    Correct
    Wrong
  • 2
    96
    Correct
    Wrong
  • 3
    192
    Correct
    Wrong
  • 4
    206
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 3. "192"
Explanation :

Answer: C) 192 Explanation: Let the third subject marks be 'x'=> Second subject marks = 2x=> Third subject marks = 4xGiven avg = 224x + 2x + 4x = 224 x 3=> 7x = 224 x 3=> x = 96Hence, Second subject marks = 2x = 2 x 96 = 192.

Q: Important component that helps in clotting of the blood is called ____. 1336 0

  • 1
    Haemoglobin
    Correct
    Wrong
  • 2
    Platelets
    Correct
    Wrong
  • 3
    Serum
    Correct
    Wrong
  • 4
    Plasma
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 2. "Platelets"
Explanation :

Answer: B) Platelets Explanation: Blood Platelets are the components of the blood that are helpful in clotting of the blood.

Q: 'Minamata' disease was caused by ? 1336 0

  • 1
    Lead
    Correct
    Wrong
  • 2
    Mercury
    Correct
    Wrong
  • 3
    Cadmium
    Correct
    Wrong
  • 4
    Zinc
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 2. "Mercury"
Explanation :

Answer: B) Mercury Explanation:

Q: What least number must be substracted from 627349 so that the remaining number is divisible by 15 ? 1336 0

  • 1
    1
    Correct
    Wrong
  • 2
    2
    Correct
    Wrong
  • 3
    3
    Correct
    Wrong
  • 4
    4
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 4. "4"
Explanation :

Answer: D) 4 Explanation: On dividing 627349 by 15, we get remainder = 4.Therefore, the obtained remainder is the least number to be subtracted from the given number so that the the mnumber is divisible by 15.Here 4 is the least number to be subtracted from 627349 so that it is divisible by 15.

Q: Gases in the atmosphere and their percentages? 1336 0

  • Show AnswerHide Answer
  • Workspace

Answer :
Explanation :

The air around us is a mixture of gases, mainly nitrogen and oxygen, but containing much smaller amounts of water and other gases. Earth's atmosphere is composed of many gases. Their percentages by volume is given by::  78% Nitrogen, 21% Oxygen, 0.9% Argon, and 0.03% Carbon dioxide  And very small percentages of other elements.

Q: What is the most commonly spoken language in the world? 1336 0

  • 1
    Mandarin Chinese
    Correct
    Wrong
  • 2
    English
    Correct
    Wrong
  • 3
    Spanish
    Correct
    Wrong
  • 4
    Hindi
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 1. "Mandarin Chinese"
Explanation :

Answer: A) Mandarin Chinese Explanation:

Q: There are 6561 balls are there out of them 1 is heavy. Find the minimum number of times the balls have to be weighted for finding out the heavy ball ? 1335 0

  • 1
    2414
    Correct
    Wrong
  • 2
    204
    Correct
    Wrong
  • 3
    87
    Correct
    Wrong
  • 4
    8
    Correct
    Wrong
  • Show AnswerHide Answer
  • Workspace

Answer : 4. "8"
Explanation :

Answer: D) 8 Explanation: Suppose there are 9 balls   Let us give name to each ball B1 B2 B3 B4 B5 B6 B7 B8 B9   Now we will divide all the balls into 3 groups.   Group1 - B1 B2 B3   Group2 - B4 B5 B6   Group3 - B7 B8 B9   Step1 - Now weigh any two groups. Let's assume we choose Group1 on left side of the scale and Group2 on the right side.   So now when we weigh these two groups we can get 3 outcomes.   Weighing scale tilts on left - Group1 has a heavy ball.Weighing scale tilts on right - Group2 has a heavy ball.Weighing scale remains balanced - Group3 has a heavy ball.Lets assume we got the outcome as 3. i.e Group 3 has a heavy ball.   Step2 - Now weigh any two balls from Group3. Lets assume we keep B7 on left side of the scale and B8 on right side.   So now when we weigh these two balls we can get 3 outcomes.   Weighing scale tilts on left - B7 is the heavy ball.Weighing scale tilts on right - B8 is the heavy ball.Weighing scale remains balanced - B9 is the heavy ball.The conclusion we get from this Problem is that each time weigh. We element 2/3 of the balls.   As we came to conclusion that Group3 has the heavy ball from Step1, we remove 6 balls from the equation i.e (2/3) of 9.   Simillarly we do the ame thing for the Step2.   Now going with this conclusion. We have 6561 balls.   Step - 1   Divided into 3 groups   Group1 - 2187Balls   Group2 - 2187Balls   Group3 - 2187Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 2   Divided into 3 groups   Group1 - 729Balls   Group2 - 729Balls   Group3 - 729Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 3   Divided into 3 groups   Group1 - 243Balls   Group2 - 243Balls   Group3 - 243Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 4   Divided into 3 groups   Group1 - 81Balls   Group2 - 81Balls   Group3 - 81Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 5   Divided into 3 groups   Group1 - 27Balls   Group2 - 27Balls   Group3 - 27Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 6   Divided into 3 groups   Group1 - 9Balls   Group2 - 9Balls   Group3 - 9Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 7   Divided into 3 groups   Group1 - 3Balls   Group2 - 3Balls   Group3 - 3Balls   Taking the similar steps as we did in the above example, we come to the conclusion that Group1 has the heavy ball.   Step - 8   So now when we weigh 2 balls out of 3 we can get 3 outcomes.   Weighing scale tilts on left - left side placed is the heavy ball.Weighing scale tilts on right - right side placed is the heavy ball.Weighing scale remains balanced - remaining ball is the heavy ball.So the general answer to this question is, it is always multiple of 3 steps.   For 9 balls  32= 9. therefore 2 steps   For 6561 balls 38 = 6561 therefore 8 steps

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully

      Report Error

    Please Enter Message
    Error Reported Successfully