(1)KNO3(KOH) ______________________________
(2)NaCl(CaCl2) ______________________________
(3)K2SO3(CaCO3) ______________________________
(4)K2SO4(K2CO3) ______________________________
(5)Na2SO4(Na2CO3) ______________________________
(6)NaHCO3(Na2CO3) ______________________________