1. A solution turns red litmus blue, its pH is likely to be:
2. The reaction of Iron (III) oxide with Aluminium is used to join railway tracks. This reaction is known as:
- (a) Decomposition reaction
- (b) Thermit reaction
- (c) Neutralization reaction
- (d) Combination reaction
3. Which of the following compounds contains the functional group –OH?
- (a) Propanone
- (b) Propanol
- (c) Propanoic acid
- (d) Propanal
4. Ethanol reacts with Sodium to form two products. These are:
- (a) Sodium ethanoate and hydrogen
- (b) Sodium ethanoate and oxygen
- (c) Sodium ethoxide and hydrogen
- (d) Sodium ethoxide and oxygen
5. Assertion (A): Ionic compounds have high melting and boiling points.
Reason (R): A large amount of energy is required to break the strong inter-ionic attraction.
- (a) Both A and R are true and R is the correct explanation of A.
- (b) Both A and R are true but R is not the correct explanation of A.
- (c) A is true but R is false.
- (d) A is false but R is true.
6. (a) Draw the electron dot structure of (i) Methane (\(CH_4\)), (ii) Nitrogen molecule (\(N_2\)).
(b) Why do covalent compounds generally have low melting and boiling points? (2 Marks)
7. Translate the following statements into chemical equations and balance them:
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (2 Marks)
8. (a) Define an Amphoteric oxide.
(b) Give the chemical formula of two amphoteric oxides.
(c) Write a balanced chemical equation to show the reaction of Zinc oxide with Sodium Hydroxide. (3 Marks)
9. Explain the chlor-alkali process for the manufacture of Sodium Hydroxide. Write the balanced chemical equation. Name the gases evolved at the anode and the cathode. (3 Marks)
10. (a) What is a Homologous series? List two characteristics.
(b) Differentiate between Saturated and Unsaturated hydrocarbons on the basis of their burning behavior.
(c) What is meant by Isomerism? Draw the structures of two isomers of Butane. (5 Marks)
OR
(a) Write the chemical equation for the reaction of Ethanoic acid with: (i) Sodium carbonate, (ii) Ethanol (in presence of acid).
(b) What is Saponification? Write the reaction involved.
(c) Why does micelle formation take place when soap is added to water?
11. Case Study: The pH of a solution varies from 0 to 14. Solutions having pH less than 7 are acidic, while those with pH greater than 7 are basic. Our body works within the pH range of 7.0 to 7.8. When pH of rain water is less than 5.6, it is called acid rain.
(i) What is the nature of toothpastes used to prevent tooth decay? (1 Mark)
(ii) How does the stinging hair of nettle leaves cause pain? (1 Mark)
(iii) (a) Why does a milkman add a small amount of baking soda to fresh milk? (2 Marks)
OR
(iii) (b) How is Plaster of Paris prepared? Write the chemical equation. (2 Marks)
12. Which of the following is the correct sequence of anaerobic respiration in yeast?
- (a) Glucose \(\rightarrow\) Cytoplasm \(\rightarrow\) Pyruvate \(\rightarrow\) Mitochondria \(\rightarrow\) Ethanol + CO2
- (b) Glucose \(\rightarrow\) Cytoplasm \(\rightarrow\) Pyruvate \(\rightarrow\) Cytoplasm \(\rightarrow\) Lactic acid
- (c) Glucose \(\rightarrow\) Cytoplasm \(\rightarrow\) Pyruvate \(\rightarrow\) Mitochondria \(\rightarrow\) CO2 + H2O
- (d) Glucose \(\rightarrow\) Cytoplasm \(\rightarrow\) Pyruvate \(\rightarrow\) Cytoplasm \(\rightarrow\) Ethanol + CO2
13. The gap between two neurons is called a:
- (a) Dendrite
- (b) Synapse
- (c) Axon
- (d) Impulse
14. In a flower, the parts that produce male and female gametes (germ cells) are:
- (a) Stamen and anther
- (b) Filament and stigma
- (c) Anther and ovary
- (d) Stamen and style
15. Which of the following constitutes a food chain?
- (a) Grass, wheat and mango
- (b) Grass, goat and human
- (c) Goat, cow and elephant
- (d) Grass, fish and goat
16. Assertion (A): The sex of a child in humans is determined by the father.
Reason (R): Males have one X and one Y chromosome.
- (a) Both A and R are true and R is the correct explanation of A.
- (b) Both A and R are true but R is not the correct explanation of A.
- (c) A is true but R is false.
- (d) A is false but R is true.
17. Assertion (A): Ozone protects the earth from harmful UV radiation.
Reason (R): CFCs are responsible for the depletion of the ozone layer.
- (a) Both A and R are true and R is the correct explanation of A.
- (b) Both A and R are true but R is not the correct explanation of A.
- (c) A is true but R is false.
- (d) A is false but R is true.
18. State one function of each of the following: (i) Cerebellum, (ii) Medulla. (2 Marks)
19. What is the placenta? Mention its role during pregnancy. (2 Marks)
20. What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem? (2 Marks)
21. (a) Draw a neat diagram of a Reflex Arc.
(b) What is the role of the spinal cord in a reflex action? (3 Marks)
22. A blue flower plant (BB) is crossed with a white flower plant (bb).
(a) What is the colour of the flowers in the F1 generation?
(b) What percentage of plants will have white flowers in F2 generation?
(c) State the ratio of genotype BB and Bb in F2 generation. (3 Marks)
23. (a) Draw a diagram of the Human Alimentary Canal and label: Stomach, Small Intestine, Liver.
(b) Explain the role of (i) Saliva in the mouth, (ii) Hydrochloric acid in the stomach.
OR
(a) Draw a schematic representation of the Double Circulation in humans.
(b) Differentiate between Arteries and Veins (any two points).
(c) Why is the separation of right and left side of the heart useful? (5 Marks)
24. Case Study: Plants respond to stimuli by growth movements. The movement of a plant part in response to light is called phototropism. The movement of plant roots towards the earth is called geotropism.
(i) Name the plant hormone responsible for the bending of a shoot towards light. (1 Mark)
(ii) Which part of the plant shows negative geotropism? (1 Mark)
(iii) (a) How do auxins promote the growth of a tendril around a support? (2 Marks)
OR
(iii) (b) State the function of (i) Gibberellins, (ii) Cytokinins. (2 Marks)
25. The image formed by a concave mirror is observed to be virtual, erect and larger than the object. The position of the object should be:
- (a) Between F and C
- (b) At C
- (c) Beyond C
- (d) Between P and F
26. The human eye forms the image of an object at its:
- (a) Cornea
- (b) Iris
- (c) Pupil
- (d) Retina
27. The magnetic field lines inside a long current-carrying solenoid are:
- (a) Curved
- (b) Parallel straight lines
- (c) Radial
- (d) Concentric circles
28. Which of the following terms does not represent electrical power in a circuit?
- (a) \(I^2R\)
- (b) \(IR^2\)
- (c) \(VI\)
- (d) \(V^2/R\)
29. Assertion (A): A current-carrying straight conductor experiences a force when placed perpendicular to the direction of a magnetic field.
Reason (R): The direction of force is given by Fleming's Left Hand Rule.
- (a) Both A and R are true and R is the correct explanation of A.
- (b) Both A and R are true but R is not the correct explanation of A.
- (c) A is true but R is false.
- (d) A is false but R is true.
30. Why does the sky appear dark instead of blue to an astronaut? (2 Marks)
31. A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens. (3 Marks)
32. (a) State Joule's Law of Heating.
(b) Two lamps, one rated 100 W at 220 V and the other 60 W at 220 V, are connected in parallel to electric mains supply. What current is drawn from the line if the supply voltage is 220 V? (3 Marks)
33. (a) State Ohm's Law. Draw a circuit diagram to verify this law.
(b) Draw a schematic diagram of a circuit consisting of a battery of three cells of 2V each, a \(5\Omega\) resistor, an \(8\Omega\) resistor, and a \(12\Omega\) resistor, and a plug key, all connected in series. Calculate the current flowing through the \(8\Omega\) resistor. (5 Marks)
OR
(a) List the factors on which the resistance of a conductor depends.
(b) Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
(c) Calculate the equivalent resistance when two resistors of \(3\Omega\) and \(6\Omega\) are connected in parallel.
34. Case Study: A student performs an experiment with a glass slab to trace the path of a ray of light. He observes that the emergent ray is parallel to the incident ray but is displaced sideways. This displacement is called lateral displacement.
(i) Name the phenomenon observed when light passes from air to glass. (1 Mark)
(ii) State Snell's Law of refraction. (1 Mark)
(iii) (a) Draw a ray diagram showing the refraction through a rectangular glass slab. Label the angle of incidence (i) and angle of emergence (e). (2 Marks)
OR
(iii) (b) If the refractive index of glass is 1.5 and the speed of light in vacuum is \(3 \times 10^8\) m/s, calculate the speed of light in glass. (2 Marks)