On heating blue coloured powder of copper (II) nitrate in a boiling tube, copper oxide (black), oxygen gas and a brown gas X is formed.
(a) Write a balanced chemical equation of the reaction.
(b) Identify the brown gas X evolved.
(c) Identify the type of reaction.
(d) What could be the pH range of aqueous solution of the gas X?

For making cake, baking powder is taken.  If at home your mother uses baking soda instead of baking powder in cake,

(a) How will it affect the taste of the cake and why?

(b) How can baking soda be converted into baking powder?

(c) What is the role of tartaric acid added to baking soda?

Explain the following
(a) Reactivity of Al decreases if it is dipped in HNO₃.
(b) Carbon cannot reduce the oxides of Na or Mg
(c) NaCl is not a conductor of electricity in solid state whereas it does conduct electricity in aqueous solution as well as in molten state.
(d) Iron articles are galvanised 
(e) Metals like Na, K, Ca and Mg are never found in their free state in nature.

Explain the mechanism of photosymthesis.

How does chemical coordination take place in animals?

With the help of a labelled circuit diagram illustrate the pattern of field lines of the magnetic field around a current carrying straight long conducting wire. How is the right hand thumb rule useful to find direction of magnetic field associated with a current carrying conductor?

Look at the below figure and answer the following questions:

a) What change would you observe in the calcium hydroxide solution taken in tube B?
b) Write the reaction involved in test tubes A and B respectively.
c) If ethanol is given instead of ethanoic acid, would you expect the same change?
d) How can a solution of lime water be prepared in the laboratory?

(a)Name the parts labelled A, B, C, D and E.
(b)Where do the following functions occur?
  (i) Production of an egg
 (ii) Fertilisation
(iii) Implantation of the zygote.
(c) What happens to the lining of uterus:
 (i) before release of a fertilised egg?
(ii) if no fertilisation occurs?

(a)List the parts of the human eye that control the amount of light entering into it. Explain how they perform this function.
(b)Write the function of retina human eye.
(c)Do you know that the corneal impairment can be cured by replacing the defective cornea with the cornea of the donated eyes?   How and why should we organise groups to motivate the community members to donate their eye after death?

Explain giving example where active involvement of local people lead to efficient management of forest.