PYQ Vault

Day 163: CBSE Class 10 Science

5 questions. Try each one first, then open its answer.

  1. Question 1

    The Human Eye and the Colourful World. Asked once: 2024 (same type asked 3 times)

    31
    Study the diagram given below and answer the questions that follow : (i) Name the defect of vision represented in the diagram. Give reason for your answer. (ii) List two causes of this defect. (iii) With the help of a diagram show how this defect of vision is corrected.

  2. Question 2

    Acids, Bases and Salts. Asked once: 2023 (same type asked 3 times)

    27
    Consider the following salts : (i) YCl\mathrm{YCl} (ii) NH4X\mathrm{NH_4X} (iii) ZCO3\mathrm{ZCO_3} (a) What would be the pH of the salt solution if in YCl\mathrm{YCl}, Y is sodium ? Give reason for your answer. (b) If in salt NH4X\mathrm{NH_4X}, X is nitrate, then its solution will give what colour with universal indicator ? Why ? (c) What would be the change in colour in blue litmus solution if ZCO3\mathrm{ZCO_3} is added to it and Z is potassium ?

  3. Question 3

    Carbon and its Compounds. Asked once: 2022 (same type asked 3 times)

    1
    (a) Write the molecular formula of the following carbon compounds : (i) Methane (ii) Propane (b) Carbon compounds have low melting and boiling points. Why ?

  4. Question 4

    Carbon and its Compounds. Asked once: 2024 (same type asked 3 times)

    34 (A)
    (i) Define a homologous series of carbon compounds. (ii) Why is the melting and boiling points of C4H8\mathrm{C_4H_8} higher than that of C3H6\mathrm{C_3H_6} or C2H4\mathrm{C_2H_4} ? (iii) Why do we NOT see any gradation in chemical properties of a homologous series compounds ? (iv) Write the name and structures of (i) aldehyde and (ii) ketone with molecular form C3H6O\mathrm{C_3H_6O}.

  5. Question 5

    Carbon and its Compounds. Asked once: 2023 (same type asked 3 times)

    34 (b)
    (i) Name the simplest saturated hydrocarbon. Draw its electron dot structure. Which type of bonds exist in this compound ? (ii) Name any two mixtures of the carbon compound used as a fuel in daily life, of which the above mentioned compound is an important component. (iii) In which homologous series of carbon compounds can this compound be placed ? Write the general formula of the series. (iv) Which type of flame is produced on burning it ?