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ALL CIE CHEMISTRY DOUBTS HERE !!

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Deadly_king:

--- Quote from: moon on October 10, 2010, 08:42:05 am ---for nov 2009 ppr 2

The oxidation state of hydrogen in the metal hydrides is always -1 so why in PH3 the oxidation state is +1 and hence x+3(-1)=0 so x=+3 really need help..Thanks n advance

--- End quote ---

Phosphorus is not a metal.

Being a non-metal, it cannot give electrons to turn onto +3 oxidation states. It has to accept electrons which is why it has a negative oxidation number  :)

moon:

--- Quote from: moon on October 10, 2010, 08:34:52 am ---why didn't we find the mole ratio CO2: H2O
so that the formula can be C2H2...

--- End quote ---


please i really need help in this question and thank a lot 4ur ppr4 explanation....

Deadly_king:

--- Quote from: moon on October 10, 2010, 08:34:52 am ---why didn't we find the mole ratio CO2: H2O
so that the formula can be C2H2...

--- End quote ---

Hmmm........it's not possible to do it using the ratio CO2 : H2O

But you must realise that :
1 mole of hydrocarbon will form x moles CO2 and y/2 moles of H2O

Ratio CO2 : H2O will hence be x : y/2

These are two unknown values which are not linked in any way. So we cannot solve it.

First you need the ratio hydrocarbon : CO2 ---> 1 : x
Then use ratio of hydrocarbon to H2O ---> 1 : y

Only then will you be able to find the values of x and y :)

moon:
thank u very much 4ur explanation... :)

Deadly_king:

--- Quote from: moon on October 10, 2010, 09:43:59 am ---thank u very much 4ur explanation... :)

--- End quote ---

You're welcome buddy.

I just hope my explanations were clear enough :)

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