The formula of exhausted permutit is :
CaAl2Si2O8xH2O
Na2Al2Si2O8.xH2O
CaB2Si2O8.xH2O
K2Al2Si2O8.xH2O
In exhausted permutit all sodium ions are replaced by Calcium or Magnesium ions
The correct formula of exhausted permuitit is :
(p) Na2Al2Si2O8.xH2O
(q) K2Al2Si2O8.xH2O
(r) MgAl2Si2O8.xH2O
(s) CaAl2Si2O8.xH2O