5-7 Predict if a precipitation reaction could occur

5-7-1. Precipitation is expected from which mixture?
A. Na2CO3(aq) + KNO3(aq)
B. AgNO3(aq) + CaCl2(aq)
C. Neither
D. Both



5-7-2. A student is given two test tubes and is told that one contains NaCl(aq), while the other test tube contain Ba(NO3)2(aq). Which precipitating reagent, if added to both test tubes would allow the student to determine their contents?
A. AgNO3(aq), B. K2SO4(aq), C. neither, D. both