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chem mcQ...

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MARKSCHEME SAYS d bt i am quite sure that it shud be B...correct me if i m wrong
 
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Mark Scheme's right:

Read the question carefully, it asks us to burn one mole of each element.

Mg + 1/2 O_2 ----> MgO
Al + 3/4 O_2 ---->1/2 Al_2 O_3
S + 3/2 O_2 ----> S0_3

Actually SO_3 shouldn't be formed in this reaction because he hasn't mentioned use of vanadium pentaoxide anywhere, but as D becomes the only option according to this trend, so D is the answer.
 
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THe actual reason is that sulfur in its natural form exists as S8... So 8 moles of O2 are required to oxidize 1 mole of sulfur completely... This is y the in increment is so sharp...! :)
 
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