List of top Science Questions

Which of the following ions can turn red litmus paper blue?
Which of the following is a heterogeneous compound?
Mushroom is:
How many trophic levels are there in a forest ecosystem?
The pH value of any neutral solution is:
Which of the following is a natural indicator?
What is the chemical formula of washing soda?
Which of the following equations is \emph{not balanced?}
The reaction in which ions are exchanged is called:
Which is an example of a decomposer?
Which of the following is/are a part of environment?
Which of the following is necessary in the synthesis of thyroxine hormone?
Which is the main source of energy on earth?
The colour of chlorophyll pigment is:
The hardest part of the teeth is:
The device which directly converts solar energy into electricity is known as:
Which one of the following is a strong base?
What is the chemical formula of dry ice?
Which one of the following proteins is responsible for the red colour of blood?
Dispersion of white light is produced by:
Those which 'produce heat on combustion' are called:
Euro-II is related to:
The actual source of energy of fossil fuel is:
Which of the following is a non-renewable source of energy?

Write notes on the following: 
(a) Saturated and unsaturated hydrocarbons 
(b) Corrosion 
(c) Precipitation reaction