chem 問題...

NH3 + HNO3 -> NH4NO3
如果要搵佢oxidation number，係搵邊個"N"黎計??

To consider whether a reaction is redox or not, all elements involved in the reactants and products must be considered.

NH3 + HNO3 → NH4NO3
To make calculations easy, an ionic compound is considered as the combination of a cation and an anion. For example, NH4NO3 is considered as NH4+ and NO3-.

The oxidation numbers of all reactants and products involved in the reaction are listed below:
a reactants aaaaaaaaaaa products
N in NH3 = -3 aaaaaaa N in NH4+ = -3
N in HNO3 = +5 aaaaa N in NO3- = +5
H in NH3 = +1 aaaaaaa H in NH4+ = +1
H in HNO3 = +1 aaaaa H in NH4+ = +1

Obviously, There is no change in redox number, and the reaction is not redox.

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即係若果我in條eqt 入面... find到其中 element of oxidation unmber unchange
Even another element have change of oxidation unmber
"That mean this eqt should not be a redox reaction!!??"

In a redox reaction, there are one pair of changes in oxidation number. One is the increase in oxidation number, and another is the decrease.

In a non-redox reaction, there is no change in oxidation number.

In a reaction, it is impossible to find only one change (either increase or decrease) in oxidation number.

still u started with N with +5 oxidation number as well, so +5 goes back to 3+ counts as the reduction?? doesnt matter. if u start with a $100 bill on your right hand and a $500 on your left hand and ending up with $100 on your left hand and $500 on your right hand. does that make any difference?? dont think so, u have to look at the whole picture. the above reaction is not even a redox reaction, simply an acid base reaction.