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FBISE Chemistry XII (2018-Second Group) 1. Which is not correct order of stability of oxidation states of group IV A elements? a) Ge +4 >Sn +4 b) Sn +4 >Pb +4 c) Ge +4 >Ge +2 d) Pb +4 >Pb +2 ... Answer is d) Explanation: Pb +2 is more stable than Pb +4 . That is why PbCl 4 is readily changed into PbCl 4 . In group IV elements, the stability order in +4 oxidation state decreases down the group while the stability order in +2 oxidation state increases down the group. Therefore above three option are correct. show Answer 2. The only akaline earth metal which reacts with alkalies is a) Be b) Mg c) Ca d) Ba ... Answer is a) Explanation: Be reacts with alkalies to form hydrogen gas and sodium bryllate Na 2 BeO 2 while other alkaline earth metals donot react. show Answer 3. Coordination of zinc in complex ion [Zn(NH 2 -CH 2 -CH 2 -NH 2 ) 3 ] +2 is a) 3 b) 4 c) 5 d) 6 ...