CBSE ADDA

MCQ By(JSunil)Based on Carbon and It’s Compound Q1. Which of the following is not a saturated hydrocarbon? (i) cyclohexane ( ii) benzene. (iii) butane (iv) isobutene Q2.The bond between two identical non metallic atom has a pair of electron? (i)un equally shared between two atoms. (ii)transferd completely from one atom to another. (iii)with identical spins (iv)equally shared between them. Q3. Covalent compounds are generally ( i)soluble in water (ii)insoluble in water (iii)ionize in water (iv)hydrolyse in water Q4. Propane with the molecular formula C3H8 has ( i) 7covalent bonds (ii) 8 covalent bonds (iii) 9 covalent bonds ( iv) 10 Covalent bonds. Q5. A hydrocarbon reacts with ammonical cuprous chloride solution to form a red precipitate .The hydrocarbon is (i) ethane (ii) ethene (iii)butane (iv)1-propyne Q6.Which of the following substance is added to denature Ethanol ? ( i)methanol (ii)pyridine (iii)copper sulphate (iv)all of

1. In our country, there are attempts to increase the height of several existing dams like Tehri and Almati, dams across Narmada. What are the reasons behind it? Ans. Dams are large water storing bodies that are usually built by government agencies across the rivers to regulate the flow of water and generate electricity. They store huge amount of water for irrigation of fields throughout the year. 2. On the banks of the river, there are several factories that are discharging effluents into the river. The pH of water sample collected from the river is found to be acidic in the range of 3.5–4.5. Name the effluents which is the most likely to cause the lowering of pH of river water. What should be the effect of pollution on the fishes of the river. Ans. Untreated sewage, garbage, some human activities like bathing, washing of clothes and immersion of ashes or unburnt corpses are the most likely causes of lowering of pH of river water. It makes the water toxic and kills the aquatic

ORAL QUESTIONS CLASS VIII MATHS TOPIC :- GEOMETRY 01.  Define a Polygon . 02. How many  sides  are  there in Quadrilateral ? 03. How many sides  are there  in Octagon ? 04. What is a regular  Polygon ? 05.  What is a Diagonal? 06. What is the sum measures  of angles  of the  Convex  Quadrilateral ? 07.  How many sides  does  Heptagon  has ? 08.  Say True / False:  The polygon  with minimum  number  of sides  is three . 09.  Tell  the formula  to  find sum of all interior  angles of a polygon. 10.  What  are  the Maximum  number  of   right  angles in  the right  angled  triangle? 11.  What is the sum of interior angles of a Parallelogram ? 12.   What  is a Parallelogram ? 13.  What  is Rhombus ? 14.  What  is Rectangle ? 15.  Name the closed  figure  with 4 sides  . 16.  What is the number of sides  in hexagon  ? 17.   How many Diagonals does  a  regular  hexagon  have? 18.   What  is the Sum of interior angles  of a Pentagon ? 19.   What is the  sum  of the me

Page 47          1. What are canal rays? Ans: Canal rays are positively charged radiation s that can pass through perforated cathode plate. These rays consist of positively charged particles known as protons 2. If an atom contains one electron and one proton, will it carry any charge or not? Ans: An atom containing one electron and one proton will not carry any charge they make an atom neutral. Page 49 3. On the basis of Thomson’s model of an atom, explain how the atom is ne utral as a whole. Ans:  According to Thomson’s model of the atom, an atom consists of equal number of negatively and positively charged particles. The negatively charged particles are embedded in the positively charged sphere and balance their charges. Thus, they make an atom neutral. 4. On the basis of Rutherford’s model of an atom, which subatomic particle is present in the nucleus of an atom? Ans: protons (positively-charged particles) 5. Draw a sketch of Bohr’s model of an atom w