PYQ Vault

Day 191: CBSE Class 10 Science

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

  1. Question 1

    Chemical Reactions and Equations. Asked once: 2023 (same type asked 4 times)

    3
    MnO2+x HCl→MnCl2+y H2O+z Cl2\mathrm{MnO_2} + x\,\mathrm{HCl} \rightarrow \mathrm{MnCl_2} + \mathrm{y\,H_2O} + \mathrm{z\,Cl_2} In order to balance the above chemical equation, the values of xx, y and z respectively are :

    Tap an option to check your answer.

  2. Question 2

    Chemical Reactions and Equations. Asked once: 2023 (same type asked 4 times)

    27
    (a) Identify the reducing agent in the following reactions : (i) 4NH3+5O2→4NO+6H2O\mathrm{4NH_3 + 5O_2 \rightarrow 4NO + 6H_2O} (ii) H2O+F2→HF+HOF\mathrm{H_2O + F_2 \rightarrow HF + HOF} (iii) Fe2O3+3CO→2Fe+3CO2\mathrm{Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2} (iv) 2H2+O2→2H2O\mathrm{2H_2 + O_2 \rightarrow 2H_2O} (b) Define a redox reaction in terms of gain or loss of oxygen.

  3. Question 3

    Control and Coordination. Asked once: 2023 (same type asked 4 times)

    29 (b)
    Name the phenomenon occurring in plants which are under the control of gravity, water and chemicals with one example each that shows the movement involved.

  4. Question 4

    Control and Coordination. Asked once: 2025 (same type asked 4 times)

    23
    Name the parts of hind-brain of the human brain. Which part of the hind-brain controls involuntary actions such as blood pressure and salivation ?

  5. Question 5

    Electricity. Asked once: 2023 (same type asked 4 times)

    36
    (i) How is electric current related to the potential difference across the terminals of a conductor ? Draw a labelled circuit diagram to verify this relationship. (ii) Why should an ammeter have low resistance ? (iii) Two V - I graphs A and B for series and parallel combinations of two resistors are as shown. Giving reason state which graph shows (a) series, (b) parallel combination of the resistors.