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Subjective-

              S.L                                    Questions                                     Ma Skill
              No.                                                                                  rk
              Q.1                                                                                  1    R
                     A  non-metal  X  exists  in  two  different  forms  V  and  Z.
                         Y is the hardest known natural substance, whereas Z
                        is a good conductor of electricity. Identify X, Y and Z. [CBSE 2011]
              Q.2                                                                                  1    u
                     Why does calcium float in water?                          [CBSE 2011]
              Q.3                                                                                  3    R+A
                     A,  B  and  C  are  three  elements  which  undergo  chemical
                         reactions according to the following equations:

                        A2O3 + 2B -----------→ B2O3 + 2A ,
                        3CSO4 + 2B ------------→  B2(SO4)3 + 3C
                        3CO + 2A ----------------→ A2O3 + 3C

                        a.   Which element is most reactive?
                        b.   Which element is the least reactive?

                        c.   What type of reactions is listed above?               [CBSE 2014]
              Q.4                                                                                  3    U+A
                     State  the  conditions  under  which  the  following  metals
                         react with water. Write chemical equation for its
                        reaction with each: (a) Na (b) Mg (c) Fe                     [CBSE 2015]
              Q.5                                                                                  5    HOT
                     Give reasons only:

                        a.      We  can  store  copper  sulphate  solution  in  a  silver
                         vessel but not silver nitrate solution in copper vessel.

                        b.      The  reaction  of  zinc  with  dilute  HNO3  does  not
                         produce H2 gas.
                        c.      Sulphur      does  not  conduct  electricity  whereas
                         magnesium conducts electricity.
                        d.   Food cans are coated with tin rather than zinc.

                          e.  Silver  ornaments  lose  their  shine  when  kept  in
                         open  air  for  sometime?                                                    [CBSE2011]
















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