Q1. N2 + 3H2 2NH3, name the type of reaction. (1)
Q2. Why do we apply paint on iron articles? (1)
Q3. Name the device which directly converts solar energy into electrical energy.
Q4. Name the instrument used to measure electric current in a circuit. (1)
Q5. Explain why most of the metals do not displace hydrogen from Nitric acid.
Q6. What is bleaching powder? How is it prepared? State two uses of bleaching
powder. (2)
Q7. What is neutralization reaction? Give one example. (2)
Q8. A white solid when dropped in water produces a hissing sound. What the
solid may be? Give the chemical reaction for above observation. Name the
product formed. (2)
Q9. How are the fats digested in our bodies and where does this process take
Q10. Out of two solar cookers one was covered by a plane glass slab and other
was left open, which of two solar cookers will be more efficient and why.
Q11. What is the (a) highest (b) lowest resistance that can be secured by
combining four coils of resistance 4, 8, 12and 24. (2)
Q12. What s meant by the term magnetic field lines? List any two properties of
magnetic field lines. (2)
Q13. An electric bulb draws a current of 0.8A and works on 250V on the average 8
hours a day, if energy costs Rs 3 per kWh. Calculate monthly bill for 30 days.
Q14. Take 2g silver chloride in a china dish and place it in sunlight:
(a) Observe the colour of silver chloride after some time
(b) What type of reaction takes place?
(c) Write the chemical reaction for above observation. (3)
Q15. What is plaster of paris? How is it prepared? State two important uses of
plaster of paris. (3)
Q16. Tooth enamel is one of the hardest substances in our body. How does it
undergo damage due to the eating of chocolates and sweets? What should
we do to prevent it? (3)
Q17. What is reflex arc? Draw diagram of reflex arc. What is the role of the brain
in reflex action? (3)
Q18. What are the different ways in which glucose...