In the given chemical reactions,2P+H2O+CO2→Q→H2O+CO2 2R→NaClS+NH4Cl identify 'S'  in the reaction

2NH3P+H2O+CO2→NH42CO3Q→H2O+CO22NH4HCO3R→2NaCl2NH4Cl+2NaHCO3S2NaHCO3→∆Na2CO3+CO2+H2OThe above  process is said to be solvay process used for manufacture of Na2CO3