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# Thermal decomposition of KHCO3 to KOH ?

## Thermal decomposition of KHCO3 to KOH ?

(OP)
Hi,

Does anyone know if it is possible to thermally decompose KHCO3 to KOH; perhaps it is possible but some specific conditions are required.

I know that KHCO3 decomposes into K2CO3, H2O and CO2 but the question is if it could decompose to KOH?

Thanks!

### RE: Thermal decomposition of KHCO3 to KOH ?

No, but that is based upon Gibbs free energies at 25 oC; need the values at 100 oC (where KHCO3 decomposes) to be sure.  Consider the reaction between possible byproducts:

K2CO3 + H2O(g) + CO2(g) = 2 KOH + 2 CO2(g)

Simplify:

K2CO3 + H2O(g) = 2 KOH + CO2(g)

ΔGRxn, 25C = 2(-378.7) - 394.4 + 1063.5 + 228.6

= +140.3 kJ/mol

Due to positive ΔGRxn, 25C, the reaction won't go.

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