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Among the following, the number of compounds than can react with PCl5 to give POCl3 is O2, CO2, SO2, H2O, H2SO4, P4O10
    Correct answer is '5'. Can you explain this answer?

    Mahi Sarkar answered
    Reactivity of Compounds with PCl5 to form POCl3

    POCl3 is a commonly used reagent for the conversion of alcohols to alkyl chlorides. It is also used in the synthesis of various organic compounds. PCl5 is a strong electrophile and can react with various compounds to form POCl3.

    Out of the given compounds:

    1. O2: It is an inert gas and does not react with PCl5 to form POCl3.

    2. CO2: It is also an inert gas and does not react with PCl5 to form POCl3.

    3. SO2: It can react with PCl5 to form POCl3. The reaction is as follows:
    SO2 + PCl5 → POCl3 + SOCl2

    4. H2O: It can react with PCl5 to form POCl3. The reaction is as follows:
    H2O + PCl5 → POCl3 + 2HCl

    5. H2SO4: It can react with PCl5 to form POCl3. The reaction is as follows:
    H2SO4 + PCl5 → POCl3 + 2HCl + SO2

    6. P4O10: It is a compound of phosphorus and can react with PCl5 to form POCl3. The reaction is as follows:
    P4O10 + 10PCl5 → 10POCl3 + PCl5

    Therefore, out of the given compounds, 5 compounds can react with PCl5 to form POCl3.

    Let f(x) = x2 and g(x) = sinx for all x ε R. Then the set of all x satisfying (f o g o g o f) (x) = (g o g o f) (x),
    where (f o g) (x) = f(g(x)), is
    • a)
    • b)
    • c)
    • d)
      2nπ, n ε {...,-2, -1,0,1, 2, ....}
    Correct answer is option 'A'. Can you explain this answer?

    Ananya Das answered
    (fogogof) (x) = sin2 (sin x2)
    (gogof) (x) = sin (sin x2)
    sin2 (sin x2) = sin (sin x2)
    ⇒ sin (sin x2) [sin (sin x2) - 1] = 0
    ⇒ sin (sin x2) = 0 or 1
    ⇒ sin x2 = nπ or 2mπ + π/2, where m, n ε I
    ⇒ sin x2 = 0
    ⇒ x2 = np  x = ± np , n Î {0, 1, 2, …}.

    A train is moving along a straight line with a constant acceleration ‘a’. A boy standing in the train throws a
    ball forward with a speed of 10 m/s, at an angle of 60° to the horizontal. The boy has to move forward by
    1.15 m inside the train to catch the ball back at the initial height. The acceleration of the train, in m/s2, is
      Correct answer is '5'. Can you explain this answer?

      Aryan Singh answered
      To determine the distance traveled by the train, we need to know the initial velocity of the train and the time it has been moving with the constant acceleration.

      Let's assume the initial velocity of the train is u (m/s), the constant acceleration is a (m/s^2), and the time it has been moving is t (s).

      The distance traveled by the train can be calculated using the equation:

      s = ut + (1/2)at^2

      where s is the distance traveled.

      If the train starts from rest (u = 0), then the equation simplifies to:

      s = (1/2)at^2

      If you provide the values of the acceleration (a) and the time (t), we can calculate the distance traveled by the train.

      The number of distinct real roots of x4 - 4x3 + 12x2 + x - 1 = 0 is
        Correct answer is '2'. Can you explain this answer?

        Pragati Mishra answered
        Problem:

        Find the number of distinct real roots of the equation:

        x^4 - 4x^3 + 12x^2 + x - 1 = 0

        Solution:

        To find the number of distinct real roots of the given equation, we can use the Descartes' rule of signs and the Intermediate Value Theorem.

        Descartes' Rule of Signs:

        The Descartes' rule of signs helps us determine the possible number of positive and negative roots in a polynomial equation by analyzing the signs of its coefficients.

        In the given equation, the signs of the coefficients are:

        - The coefficient of x^4 is positive.
        - The coefficient of x^3 is negative.
        - The coefficient of x^2 is positive.
        - The coefficient of x is positive.
        - The constant term is negative.

        According to the Descartes' rule of signs, the number of positive roots of the equation is either the same as the number of sign changes in the coefficients or less than that by an even number.

        In this case, there is only one sign change, so the number of positive roots is either 1 or 0.

        Similarly, if we consider the equation f(-x), the number of negative roots is either 1 or 0.

        Intermediate Value Theorem:

        The Intermediate Value Theorem states that if a polynomial function f(x) is continuous on the interval [a, b] and f(a) and f(b) have opposite signs, then there exists at least one root of the equation f(x) = 0 in the interval (a, b).

        Analysis:

        To determine the number of distinct real roots, we need to find the number of sign changes in the coefficients and analyze the intervals where the function changes sign.

        Let's analyze the equation:

        f(x) = x^4 - 4x^3 + 12x^2 + x - 1

        - There is one sign change from positive to negative between the terms -4x^3 and 12x^2, indicating that there is one negative root.
        - There is no sign change between the terms 12x^2 and x, indicating that there are no positive roots.
        - There is one sign change between the terms x and -1, indicating that there is one positive root.

        Conclusion:

        Based on the Descartes' rule of signs and the analysis of sign changes, we can conclude that the given equation has exactly 1 positive root and 1 negative root. Therefore, the total number of distinct real roots is 2.

        Let L be a normal to the parabola y2 = 4x. If L passes through the point (9, 6), then L is given by
        • a)
          y - x + 3 = 0
        • b)
          y + 3x - 33 = 0
        • c)
          y + x - 15 = 0
        • d)
          y - 2x + 12 = 0
        Correct answer is option 'A,B,D'. Can you explain this answer?

        y2 = 4x
        Equation of normal is y = mx – 2m – m3.
        It passes through (9, 6)
        ⇒ m3 – 7m + 6 = 0
        ⇒ m = 1, 2, – 3
        ⇒ y – x + 3 = 0, y + 3x – 33 = 0, y – 2x + 12 = 0.

        The number of hexagonal faces that are present in a truncated octahedron is
          Correct answer is '8'. Can you explain this answer?

          Divya Menon answered
          Truncated Octahedron and Hexagonal Faces:
          The truncated octahedron is a polyhedron with 14 faces, 36 edges, and 24 vertices. It is created by truncating an octahedron by cutting off its corners. This results in a solid shape with hexagonal and square faces.

          Number of Hexagonal Faces:
          - The truncated octahedron has a total of 8 hexagonal faces.
          - Each hexagonal face is formed by truncating the corners of the original octahedron.
          - Since there are 8 corners in an octahedron, each corner truncation results in a hexagonal face.
          - Therefore, the truncated octahedron has 8 hexagonal faces in total.
          In conclusion, the number of hexagonal faces present in a truncated octahedron is 8.

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