What effect does the concentration of H⁺(aq) ions have on the nature of the solution?

When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.

Outline a project which aims to find the dominant coat colour in dogs.

Draw the structure for the following compounds.                

       (i)    Ethanoic acid             (ii)   Bromopentane*
       (iii)  Butanone                   (iv)   Hexanal.

*Are structural isomers possible for bromopentane?

A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?

How is the sex of the child determined in human beings?

(a)  What property do all elements in the same column of the Periodic Table as boron have in common?
(b)  What property do all elements in the same column of the Periodic Table as fluorine have in common?

Calculate the number of electrons constituting one coulomb of charge.

What is an homologous series? Explain with an example.

Why is variation beneficial to the species but not necessarily for the individual?

A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?

Oil and fat containing food items are flushed with nitrogen. Why?

How is the small intestine designed to absorb digested food?

What would you observe when zinc is added to a solution of iron(II) sulphate? Write the chemical reaction that takes place.

What are the differences between autotrophic nutrition and heterotrophic nutrition?

State two ways to prevent the rusting of iron.

What are the disadvantages of fossil fuels?

What is the role of the acid in our stomach?

How is the concentration of hydroxide ions (OH^-) affected when excess base is dissolved in a solution of sodium hydroxide?

State the principle of an electric generator.

Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.