a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbon.

b) Name the products formed when ethane burns in the air. Write a balanced chemical equation for the reaction showing the types of energies liberated.

c) Why is the reaction between methane and chlorine in the presence of sunlight considered a substitution reaction?

(a) Define the following terms in the context of spherical mirrors:

i) Pole

ii) Centre of curvature

iii) Principal axis

iv) Principal focus

b) Draw ray diagrams to show the principal focus of a 

i) concave mirror
ii) convex mirror

c) Consider the following diagram in which M is a mirror and P is an object and Q is its magnified image formed by the mirror. 

33. (a) Draw a ray diagram to show the formation of an image by a convex lens when an object is placed in front of the lens between its optical centre and principal focus.


(b) In the above ray diagram, mark the object distance (u) and the image distance (v) with their proper signs (+ve or –ve as per the new Cartesian sign convention) and state how these distances are related to the focal length (f) of the convex lens in this case.

(c) Find the power of a convex lens which forms a real and inverted image of magnification –1 of an object placed at a distance of 20 cm from its optical centre.

(a) Write the functions of the following parts in human female reproductive system:

(i) Ovary
(ii) Oviduct
(iii) Uterus

(b) Describe the structure and function of placenta. 

What is meant by speciation? List four factors that could lead to speciation. Which of them cannot be a major factor in the speciation of a self pollinating plant species. Give reason to justify your answer.