Condition for reactions

[starCr]

hello,

I would like to know if following reactions are possible/correct and under what condition:
2NaOH+K->KOH+NaOH

and

HCN+K->KCN+H

Theoretically it should be possible but I'm not sure,Please help me understand

Thanks

 

[minerva]

hello,

I would like to know if following reactions are possible/correct and under what condition:
2NaOH+K->KOH+NaOH

and

HCN+K->KCN+H

Theoretically it should be possible but I'm not sure,Please help me understand

Thanks

2NaOH+K->KOH+NaOH

This reaction isn't balanced. You start with 2 Na, but finish with one. For a candidate reaction to be a possible "real" reaction, it must be balanced.

You could remove a redundant NaOH from both sides of that reaction, so you get:

NaOH + K --> KOH + Na

I've added on an extra Na to make it balanced.

Yes, this reaction is plausible. K metal added to molten NaOH would reduce the sodium.

HCN+K->KCN+H

K is very reactive. It reacts with many things, like water for example. Can you write an equation for the reaction of K metal with water?

HCN is an acid. Will an acid react with K? Would, say, HCl react with K? Yes, it will, even more violently than the potassium will react with water.

To make the reaction more correct, double everything up in the reaction and change the hydrogen to molecular H₂.

In an aqueous solution, though, the reaction between the acid and the potassium will compete with the reaction between the water and the potassium.

 

[starCr]

Thanks for your answer Minerva,

but i didn't understood this proposition:
"In an aqueous solution, though, the reaction between the acid and the potassium will compete with the reaction between the water and the potassium."
You say that there is an aqueous solution of HCN? Supposing it exist that means that
HCN(aqueous solution) + K -> KCN + H which will fume? Can you provide an equation for this?

About H2O+K as far as I know will burn until the quantity of K will end

Thanks

 

[Borek]

No, it doesn't necessarily mean HCN must be in a form of aqueous solution, it can be in gaseous form as well. However, chemistry in presence of water will be slightly different, so it is worth of noting the difference, especially when conditions are not clearly stated.

Note, that when using HCN solution, even if K reacts initially with water, resulting base will later neutralize HCN, so the final effect and overall reaction equation will be basically the same.

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