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Offline Ghost Of Highbury

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chemistry doubt!
« on: September 04, 2009, 05:27:29 pm »
okk..a doubt in reduction and oxidation

1) C4H8 + 6O2 --> 4CO2   +   4H2O

is this reduction, oxidation or reduction and why?

i strongly think that it is oxidation as oxygen is added...however, the oxidation state of "oxygen" decreases from -4 to -6

so its redox...
plzz..helpp!!

2.) 2KNO3=2KNO2+O2
      
   this equation is so messed up for oxidation states


    there are three elements in 1 compund ...how do u determine the oxidation states for them

plzz help!! is it oxidation reduction or redox..(plz explain the reason too!


thanks a lot!!
    
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Offline astarmathsandphysics

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Re: chemistry doubt!
« Reply #1 on: September 04, 2009, 10:52:42 pm »
It is oxidation cos oxygen goes from the pure state to a compound.
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Offline astarmathsandphysics

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Re: chemistry doubt!
« Reply #2 on: September 04, 2009, 10:54:14 pm »
The 2nd is reduction cos oxygen returns to the pure state.
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Offline Ghost Of Highbury

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Re: chemistry doubt!
« Reply #3 on: September 05, 2009, 06:15:35 am »
but...do v take the oxidation stte of oxygen in both the reactions...

if so...the oxidation state decreases and thus the 1st one becomes redox right?

also, can u explain the second reaction with the oxidation states...

thanks !
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Offline Ghost Of Highbury

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Re: chemistry doubt!
« Reply #4 on: September 06, 2009, 03:23:48 pm »
nid404 plz answer
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Offline someone

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Re: chemistry doubt!
« Reply #5 on: October 06, 2009, 02:36:35 pm »
C4H8 + 6O2 --> 4CO2   +   4H2O

In first reaction, the C and H is oxidised (4 C gain 8 oxygen, 4 H gain 4 oxygen) while the O molecule is reduced

Redox is a reaction where oxidation and reduction happen simultaneously
In every reaction where there is oxidation, reduction reaction will also occurs.
These kind of reactions is called redox reaction
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nid404

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Re: chemistry doubt!
« Reply #6 on: October 06, 2009, 02:52:11 pm »
The first one is redox...cuz both oxidation and reduction take place as you suggested....and also one more point to remember....redox also can be identified if one substance gains oxygen(oxidised) and other substance gains hydrogen(reduced)

For the second one

2KNO3=2KNO2+O2

I'll let you know how to find oxidation states
you know K is +1 and O is 2-.....+1-6+x(state of N)=0
N=+5
in product KNO2
+1-4+x=0
x=3
state of N is 3.....it's getting reduced
O gets oxidised....since O2 has oxidation state 0
this is also redox
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nid404

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Re: chemistry doubt!
« Reply #7 on: October 07, 2009, 06:56:40 am »
Did u get it or not??
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Offline Ghost Of Highbury

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Re: chemistry doubt!
« Reply #8 on: October 07, 2009, 07:02:18 am »
yah yah ..got it!
thanks a lot!
 :D
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nid404

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Re: chemistry doubt!
« Reply #9 on: October 07, 2009, 07:02:49 am »
kk....ur welcome
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Offline toobeerajpanchoo

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Re: chemistry doubt!
« Reply #10 on: October 07, 2009, 07:37:31 am »
1) C4H8 + 6O2 --> 4CO2   +   4H2O
IT IS BOTH REDUCTION AND OXIDATION
BECAUSE OXIDATION TO OCCUR WE NEED THESE CONDITIONS:
1.GAIN OF OXYGEN
2.LOSE OF HYDROGEN
3.LOSE OF ELECTRON
4.INCREASE IN OXIDATION STATE
FOR REDUCTION TO OCCUR IT IS THE OPPOSITE OF OXIDATION

IN THIS EQUATION:
CARBON GAINED OXYGEN
AND LOSE HYDROGEN

OXYGEN GAINED HYDROGEN HENCE REDUCTION
OVERALL IT IS A REDOX REACTION
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Offline chemicalvarun

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Re: chemistry doubt!
« Reply #11 on: October 20, 2009, 07:20:21 am »
lol,it is redox.every reaction is both reduction and oxidation and one oxidises and the other gets reduced
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