CBSE ADDA

Q.1 Why is carbon tetravalent ? Ans 1:Carbon atom has 4 electrons in the outermost shell.It needs 4 more electrons to complete its octet. Therefore , carbon is tetravalent .  Q.2 The formula of a hydrocarbon is Cn H2n. Name the family to which it belongs and also predict its nature.   Ans 2: The hydrocarbon belongs to alkenes It is unsaturated in nature .  Q.3 What is the valency of carbon in CH3-CH3, CH2=CH2 and HC=CH ?  Ans 3: The valency of carbon in all its compounds whether saturated or unsaturated is 4.  Q.4 Out of butter and ground nut oil , which is unsaturated in Nature?  Ans 4: Groundnut oil is unsaturated in nature .  Q.5 Why is high temperature not favourable for alcoholic fermentation?  Ans 5: The high temperature destroys the enzymes which are needed to carry fermentation .  Q.6 Name a cyclic unsaturated hydrocarbon, containing three double bonds?   Ans 6: Benzene  Q.7 What is the difference in the molecula...

1. Which one of the following constitutes the two best reasons for distinguishing the living from the non living? (a) Growth and locomotion (b) Irritability and locomotion (c) Respiration and excretion (d) Reproduction and locomotion C 2.The largest living bird is (a)duck (b’) dodo (c)ostrich (d) peacock C 3. Which of the following are the only mammals that possess nucleated red blood corpuscles? I.Camel 2.Llama 3.Man 4.Dog a) l and 2 (b) 2 and 3 (c )3 and 4 (d)l and4 A 4 When compared to the mammals, birds are less sensitive to temporary deprivation of water, be cause (1.A.S.1990) (a) urea excretion in mammals entails a greater loss of water than that in birds. (A’) the water requirement per unit weight is less in birds than in mamtnals. (c) absorption of water from the gut is more efficient in birds than in mammals. (d) None of these B 5. Birds get thrust (forward motion) and lift (upward motion) from (a) air sacs . b) flapping of wings (c) twisting...

 Objective question in the form of general science for upcomming exams. SOLVED OBJECTIVE QUESTION IN THE FORM OF GENERAL SCIENCE FOR UPCOMMING EXAMS.  1. The respiration is carried on by  (A) Kidneys  (B) Brain  (C) Intestine  (D) Lungs  Ans (D)  2. Which is the outer protective cover of the body?  (A) Skeleton  (B) Hair  (C) Skin  (D) None of these  Ans (C)  3. Which collects the blood from the organs?  (A) Arteries  (B) Veins  (C) Lungs  (D) Nerves  Ans (B)  4. Which removes waste materials from the body?  (A) Kidneys  (B) Lungs  (C) Heart  (D) Brain  Ans (A)  5. Which of the following is well developed and functional in grazing animals?  (A) Appendix  (B) Liver  (C) Duodenum  (D) Rectum  Ans (A)  6. How many teeth will the children have?  (A) 10  (B) 15  (C) 28  (D) 20  Ans (D)  7. What is inner ...

CBSE ADDA 1. The type of glass used in making lenses and prisms is? (a) soft glass (b) pyrex glass (c)jena glass (d) flint glass 2. Wood is the main raw material for the manufacture of ? (a) paint (b) paper (c) ink (d) gun powder 3. How does common salt help in separating soap from the solution after saponification? (a) By decreasing solubility of soap (b) By increasing solubility of soap (c) By decreasing density of soap (d) By increasing density of soap 4. Which of the following is commonly called a ‘polyamide’? (a) Rayon (b) orlon (c)Terylene (d) Nylon 5. The major ingredient of leather is ? (a)carbohydrate (b) collagen (c)polymer (d) nucleic acid 6. In the manufacture of safety matches, which of the following materials are used to coat the two sides of match boxes? 1. Yellow phosphorus 2. Glue 3, Glass powder 4. Red phosphorus (a) l, 2 and 3 (b) l,3 and 4 (c) l,2 and 4 (d) 2,3and4 7. Glass is made of the mixture of ? (a)quartz and mica (b) sand and s...

Which instrument is used to measure pressure? Saccharimeter Ammeter Manometer Lactometer What does Angstrom measure? Quantity of liquid Length of light waves Length of cables Speed of ships Light year is related to Energy Speed Distance Intensity Match the following columns Column 1 Column 2 A. Relative 1. Pyrometer humidity B. Anemometer 2. High temperature C. Navigation 3. Hygrometer D. Direction of wind 4. Chronometer 1 2 3 4 a. B D A C b. D B A C c. A D B C d. C A D B Which of the following instruments is used to measure pressure of gases? Barometer Manometer Ammeter None of these Joule is the unit of Temperature pressure Energy Heat How many Dynes are there in one gram weight? 900 375 981 250 How many Ergs are these in 1 Joule? 102 104 106 107 The unit of current is Ohm Watt Ampere None of these The unit of energy in MKS system is Volt Erg Ohm Joule The intensity of an earthquake is measured with a Barometer H...

1. Which of the following is not an ore of Aluminium? (A) Felsper (B) Bauxite (C) Cryolite (D) Azurite 2. Most soluble in water is — (A) Camphor (B) Sugar (C) Sulphur (D) Common Salt 3. Bromine is — (A) colourless gas insoluble in water (B) A highly inflammable gas (C) A Black solid. (D) A red liquid. 4. The metal used in storage batteries — (A) Iron (B) Copper (C) Lead (D) Zinc 5. Water has maximum density at — (A) –4°C (B) 0°C (C) 4°C (D) 100°C 6. The chemial name of Uria is — (A) Aneurin (B) Chloroetane (C) Carbamide (D) None of these 7. Permanent hardness of water can be removed by adding — (A) Potassium Permanganate (B) Chlorine (C) Bleaching Powder (D) Washing Soda 8. The formula of Plaster of Paris is — (A) CaSO 4 (B) CaSO 4 , 2H 2 O (C) 2CaSO 4 , 4H 2 O (D) 2CaSO 4 , H 2 O 9. Which of the following substance is a bad conductor of electricity but a good conductor of heat? (A) Asbestos (B) Celluloid (C) Purspecks (D) Mica 10. Carborandum is — (A) Silicon Dioxide (B) Silicon Carbi...

1. Which of the following is the lightest metal ? (A) Mercury (B) Silver (C) Lithium (D) Lead 2. The most important ore of Aluminium is — (A) Bauxite (B) Calamine (C) Calcite (D) Galena 3. The element present in the largest amount in rocks and minerals is — (A) Carbon (B) Silicon (C) Hydrogen (D) Aluminium 4. An alloy used in making heating elements for electric heating devices is — (A) Solder (B) Alloysteel (C) Nichrome (D) German Silver 5. German Silver is an alloy of — (A) Copper, Silver & Nickel (B) Silver, Copper & Aluminium (C) Zinc, Copper & Nickel (D) Silver, Zinc & Nickel 6. Air is a/an — (A) Compound (B) Element (C) Mixture (D) Electrolyte 7. Which of the following is the best conductor of Electricity ? (A) Ordinary water (B) Sea water (C) Boiled water (D) Distilled water 8. Balloons are filled with — (A) Helium (B) Oxygen (C) Nitrogen (D) Argon 9. The charcoal used to decolourise raw sugar is — (A) Animal charcoal (B) Sugar charcoal (C) Cocoanut charcoal (D)...