How to predict (know) the products of the reaction SnO+NaOH? [duplicate]








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[How can I predict if a reaction will occur between any two (or more) substances?](/questions/50684/how-can-i-predict-if-a-reaction-will-occur-between-any-two-or-more-substances)

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Closed 6 years ago.



I would like to know how to complete the reaction $\ce{SnO}+\ce{NaOH ->}$, how can I form a salt and water from this?


I've seen that the complete reaction is:


$$
\ce{SnO + 2NaOH ->Na2SnO2 + H2O}
$$


How to know what will be formed?




I've discovered the answer, at least I guess...


The given reaction is 


$$
\ce{SnO + 2NaOH -> Sn^{2+} + O^{2-} + 2Na+ + 2OH-}
$$


The hidroxy breaks in $\ce{H2O + O^{2-}}$. This released oxigen will get together with the oxigen from the $\ce{SnO}$, to form $\ce{O2^{2-}}$. 


$$
\ce{SnO + 2NaOH -> Sn^{2+} + \underbrace{O2^{-2}}\_{\textrm{nox = -4}} + 2Na+ + H2O}
$$


The oxidation state of this molecule is -4. Performing the double replacement reaction we get


$$
\ce{SnO + 2NaOH -> SnO2^{-2} + 2Na+ + H2O}
$$ 


And finally,


$$
\ce{SnO + 2NaOH -> Na2SnO2 + H2O}
$$


What is already balanced.


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