| Write the next homologue of each of the following: |
| (i) \[{{C}_{2}}{{H}_{4}}\] |
| (ii) \[{{C}_{4}}{{H}_{6}}\] |
| When ethanol reacts with ethanoic acid in the presence of cone. \[{{\mathbf{H}}_{\mathbf{2}}}\mathbf{S}{{\mathbf{O}}_{\mathbf{4}}},\] a substance with fruity smell is produced. Answer the following: |
| (i) State the class of compounds to which the fruity smelling compounds belong. Write the chemical equation for the reaction and write the chemical name of the product formed. |
| (ii) State the role of cone. \[{{H}_{2}}S{{O}_{4}}\] in this reaction. |
| Calcium is an element with atomic number 20. Stating reason answer each of the following questions: |
| (i) Is calcium a metal or non-metal? |
| (ii) Will its atomic radius be larger or smaller than that of potassium with atomic number 19? |
| (iii) Write the formula of its oxide. |
| Name the parts A, B and C shown in the following diagram and state one function of each. |
 |
| In one of his experiments with pea plants Mendel observed that when a pure tall pea plant is crossed with a pure dwarf pea plant, in the first generation, \[{{\mathbf{F}}_{\mathbf{1}}}\] only tall plants appear. |
| (a) What happens to the traits of the dwarf plants in this case? |
| (b) When the \[{{\mathbf{F}}_{\mathbf{1}}}\] generation plants were self-fertilised, he observed that in the plants of second generation, \[{{\mathbf{F}}_{2}}\] both tall plants and dwarf plants were present. Why it happened? Explain briefly. |
| Draw the following diagram, in which a ray of light is incident on a concave/convex mirror, on your answer sheet. Show the path of this ray, after reflection, in each case. |
 |
| Give reason to justify the following: |
| (a) The existence of decomposers is essential in a biosphere. |
| (b) Flow of energy in a food chain is unidirectional. |
| (a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbon. [5] |
| (b) Name the products formed when ethane burns in air. Write the balanced chemical equation for the reaction showing the types of energies liberated. |
| (c) Why is reaction between methane and chlorine in the presence of sunlight considered a substitution reaction? |
| (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. |
| (a) Define the following terms in the context of spherical mirrors: [5] |
| (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. |
 |
| State the type of the mirror M and one characteristic property of the image Q. |
| (a) Draw a ray diagram to show the formation of 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 function of each of the following parts of human eye: Cornea; iris; crystalline lens; ciliary muscles. |
| (b) Millions of people of the developing countries of world are suffering from corneal blindness. These persons can be rules by replacing the defective cornea with the cornea of a donated eye. A charitable society of your city has organized a campaign in your neighbourhood in order to create awareness about this fact. If you are asked to participate in this mission how would you contribute in this noble cause? |
| (i) State the objective of organising such campaigns. |
| (ii) List two arguments which you would give to motivate the people to donate their eyes after death. |
| (iii) List two values which are developed in the persons who actively participate and contribute in such programmes. |
| Which of the following sets of materials can be used for conducting a saponification reaction for the preparation of soap? |
| (a) \[Ca{{(OH)}_{2}}\] and neem oil |
| (b) \[NaOH\] and neem oil |
| (c) \[NaOH\] and mineral oil |
| (d) \[Ca{{(OH)}_{2}}\] and mineral oil |
| A student takes four test tubes marked P, Q, R and S of 25 mL capacity and fill 10 mL of distilled water in each. He dissolves one spoon full of four different salts in each as - KCl in P, NaCI in Q, CaCl; in R and MgCl; in S. He then adds about 2 mL of a sample of soap solution to each of the above test-tubes. On shaking the contents of each of the test-tubes, he is likely to observe a good amount of lather (foam) in the test tubes marked: |
| (a) P and Q |
| (b) R and S |
| (c) P, Q and R |
| (d) P, Q and S |
| Consider the following comments about saponification reactions: |
| I Heat is evolved in these reactions |
| II For quick precipitation of soap sodium chloride is added to the reaction mixture |
| III Saponification reactions are special kind of neutralisation reactions |
| IV Soaps are basic salts of long chain fatty acids |
| The correct comments are: |
| (a) I, II and III |
| (b) II, III and IV |
| (c) I, II and IV |
| (d) Only I and IV |
| A student has to perform the experiment ?To identify the different parts of an embryo of a dicot seed.? Select from the following an appropriate group of seeds: |
| (a) pea, gram, wheat |
| (b) red kidney bean, maize, gram |
| (c) maize, wheat, red kidney bean |
| (d) red kidney bean, pea, gram |
| Which of the following is a correct set of homologous organs? |
| (a) Forelimbs of frog, bird and lizard |
| (b) Spine of cactus and thorn of bougainvillea |
| (c) Wings of bat and wings of butterfly |
| (d) Wings of a bird and wings of a bat |
| A student obtained a sharp image of a candle flame placed at the distant end of the laboratory table on a screen using a concave mirror to determine its focal length. The teacher suggested him to focus a distant building about 1 km far from the laboratory, for getting more correct value of the focal length. In order to focus the distant building on the same screen the student should slightly move the: |
| (a) mirror away from the screen |
| (b) screen away from the mirror |
| (c) screen towards the mirror |
| (d) screen towards the building |
| To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always: |
| (a) erect and laterally inverted |
| (b) erect and diminished |
| (c) inverted and diminished |
| (d) virtual, inverted and diminished |
| Select from the following the best experimental set-up for tracing the path of a ray of light passing through a rectangular glass slab: |
 |
| (a) P (b) Q |
| (c) R (d) S |
| Study the following figure in which a student has marked the angle of incidence \[(\angle i),\] angle of refraction \[(\angle r),\] angle of emergence \[(\angle e),\] angle of prism \[(\angle A)\] and the angle of deviation \[(\angle D)\]. The correctly marked angles are: |
 |
| (a) \[\angle A\] and \[\angle i\] |
| (b) \[\angle A,\,\angle i\] and \[\angle r\] |
| (c) \[\angle A,\,\angle i,\,\angle e\] and \[\angle D\] |
| (d) \[\angle A,\,\angle i,\,\angle r\] and \[\angle D\] |
| What do you observe when you drop a few drops of acetic acid to a test-tube containing: |
| (i) phenolphthaiein |
| (ii) distilled water |
| (iii) universal indicator |
| (iv) sodium hydrogen carbonate powder |
| A student focuses the image of a well illuminated distant object on a screen using a convex lens. After that he gradually moves the object towards the lens and each time focuses its image on the screen by adjusting the lens. |
| (i) In which direction-towards the screen or away from the screen, does he move the lens? |
| (ii) What happens to the size of the image-does it decrease or increase? |
| (iii) What happens to the image on the screen when he moves the object very close to the lens? |
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