Qualification > Sciences
CHEMISTRY PAPER 1 HERE
nid404:
--- Quote from: Bani on June 11, 2009, 06:00:38 pm ---
--- Quote from: sweetest angel on June 11, 2009, 05:51:43 pm ---
--- Quote from: Bani on June 11, 2009, 05:47:16 pm ---thanks a lot everyone!
someone please try answering my previous question (M/J 2007, Q16-----the one about redox reaction) Why is the answer C?
--- End quote ---
since in equation 3 no reactants have lost or gained electrons, oxygen or hydrogen!
--- End quote ---
Ya,but why is equation 1 and 2 REDOX?
1 and 2 are only oxidation, not reduction...
please help...
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it's a little difficult to explain
but i'll try...in the first one Sulphur gains oxygen atoms(oxidation) but oxygen gains electrons(reduction).
in the second one sulphur gains oxygen but oxygen gains electrons
whereas in third one although oxygen is gained, there is no transfer of electrons and hydrogen does not lose oxygen but combines with SO4
It's very difficult to explain.
* Oxygen's oxidation state reduces in the covalent bond it forms with sulphur
girl_92:
its not a que which can be explaind the best thing u can do is to go through ur notes n eat ur teachers head if u get her n u have time
Ghost Of Highbury:
--- Quote from: eddie_adi619 on June 11, 2009, 06:15:43 pm ---S has many oxidation states including -2,0,2,4,6...
in this particular reaction the oxidation state of S is "+2"
a decrease in oxidation state - reduction
an increase in oxidation state - oxidation
1.) S + O2 -> SO2
here at the left handside, as sulphur exists itself (not compound), the oxidation state is 0
at the right hand sidde it forms a compound and gains an oxidation state of +2 = this is oxidation
whereas O has an oxidation state of "0" in the left hand side and decreases to -4 in the right hand side
this is reduction
therefore its redox
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for the second equation
i can notice the decrease in oxidation state of oxygen
but not sulphur
the oxidation state of sulphur doesn't change
---
maybe this too is called a redox...
sry
but i think the first one's explanation is correct
girl_92:
bye ppl g2g bst of luck 4 2morrow
nid404:
--- Quote from: eddie_adi619 on June 11, 2009, 06:21:53 pm ---
--- Quote from: eddie_adi619 on June 11, 2009, 06:15:43 pm ---S has many oxidation states including -2,0,2,4,6...
in this particular reaction the oxidation state of S is "+2"
a decrease in oxidation state - reduction
an increase in oxidation state - oxidation
1.) S + O2 -> SO2
here at the left handside, as sulphur exists itself (not compound), the oxidation state is 0
at the right hand sidde it forms a compound and gains an oxidation state of +2 = this is oxidation
whereas O has an oxidation state of "0" in the left hand side and decreases to -4 in the right hand side
this is reduction
therefore its redox
--- End quote ---
for the second equation
i can notice the decrease in oxidation state of oxygen
but not sulphur
the oxidation state of sulphur doesn't change
---
maybe this too is called a redox...
sry
but i think the first one's explanation is correct
--- End quote ---
sulphur gains oxygen atoms..so that is oxidation whereas oxygen's oxidation state falls which is reduction
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