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                     C lass 12 chapter 10 cbse important questions  1. Out of chlorobenzene and cyclohexyl chloride which one is more reactive towards nucleophilic  substitution reaction and why ?  CBSE 2019  Answer : it is due to resonance the c-cl bond in chlorobenzene having partial double bond character which makes the substitution of chlorine more difficult in chlorobenzene than in cyclohexyl chloride where the c-cl bond has pure single bond character . 2. Why is t-butyl bromide more reactive towards sn1 reaction as compare to n-butyl bromide ?cbse 19  answer : due to higher stability of tertiary carbocation then n-butyl bromide  3. why chloroform is stored in dark coloured bottles completely filled so that air is kept out ? CBSE 2110  Answer: because chloroform is slowly oxides by air and formed poisonous gas phosgene                2CHCl3 +O2 >>...

Exercise Questions 1. Fill in the blanks. (a) A place where animals are protected in their natural habitat is called _________. (b) Species found only in a particular area is known as _______. (c) Migratory birds fly to faraway places because of __________ changes. Soln: (a) A place where animals are protected in their natural habitat is called  Sanctuary. (b) Species found only in a particular area is known as  endemic . (c) Migratory birds fly to faraway places because of  climatic  changes. 2. Differentiate between the following. (a) Wildlife sanctuary and biosphere reserve (b) Zoo and wildlife sanctuary (c) Endangered and extinct species (d) Flora and fauna Soln: (a) Wildlife sanctuary Biosphere Reserve An area within which wild animals are protected from external dangers like hunting An area constructed for the conservation of biodiversity Adequate habitat and protection are provided for the wild animals living in a sanctuary Several life forms like plants, anim...

Question 1. What do you understand by the motion of an object ? Answer: An object is said to be in motion if its position change:, with time. More Resources Previous Year Question Papers for CBSE Class 9 Science NCERT Solutions for Class 9 Science NCERT Exemplar Solutions for Class 9 Science Value Based Questions in Science for Class 9 HOTS Questions for Class 9 Science Question 2. What is a reference point ? Answer: A fixed point with respect to which the given object changes its position. Question 3. Is it possible that the train in which you are sitting appears to move while it is at rest ? Answer: Yes. The train at rest in which we are sitting appears to move when we look at another train moving parallel to the track on which our train is standing. Question 4. Define the term “distance”. – Answer: The length of actual path travelled by an object in the given time is called the distance travelled by the object. Question 5. Is distance a scalar or a vector quantity ? Answer: Distance...