Na2CO3 can be manufactured by Solvay’s process but K2CO3 cannot be prepared because
KHCO3 is more soluble than NaHCO3
KHCO3 is more soluble than NaHCO3 is correct as the electropositive character increases on moving down the group, the stability of bicarbonates increases in the same order. NaHCO3 is made by saturating a solution of sodium carbonate with carbon dioxide. The white crystalline power of NaHCO3 being less
soluble, gets separated out NaHCO3→H2O+CO2→2NaHCO3