Jun 16, 2007 #1 piateczka Chemical Jun 16, 2007 6 0 0 NL 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!
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!
Jun 16, 2007 #2 kenvlach Materials Apr 12, 2000 2,514 0 0 US No, but that is based upon Gibbs free energies at 25 [sup]o[/sup]C; need the values at 100 [sup]o[/sup]C (where KHCO[sub]3[/sub] 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) [Δ]G[sub]Rxn, 25C[/sub] = 2(-378.7) - 394.4 + 1063.5 + 228.6 = +140.3 kJ/mol Due to positive [Δ]G[sub]Rxn, 25C[/sub], the reaction won't go. Upvote 0 Downvote
No, but that is based upon Gibbs free energies at 25 [sup]o[/sup]C; need the values at 100 [sup]o[/sup]C (where KHCO[sub]3[/sub] 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) [Δ]G[sub]Rxn, 25C[/sub] = 2(-378.7) - 394.4 + 1063.5 + 228.6 = +140.3 kJ/mol Due to positive [Δ]G[sub]Rxn, 25C[/sub], the reaction won't go.