Between which pairs of substances is a chemical reaction possible if the salt is dissolved in water

Between which pairs of substances is a chemical reaction possible if the salt is dissolved in water: a) Cu and NaCl b) Hg (NO3) 2 and Pb c) Cu and Pb (NO3) 2? Write the equations of possible reactions in full ionic form.

To answer this question, it is necessary to use a range of metal activities. The metal from the solution of its salt can displace those metals that are to the left in this row, that is, they are more active.
a) Between copper Cu and sodium chloride solution NaCl, the reaction is impossible, because copper in the row of metal activity is located to the right of sodium: copper metal is less active than sodium.
b) Between lead Pb and a solution of mercury nitrate Hg (NO3) 2, a reaction is possible. Lead metal is located in the row of metal activity to the left of mercury, it is more active.
Pb + Hg(NO₃)₂ → Pb(NO₃)₂ + Hg↓
Pb⁰ + Hg²⁺ + 2 NO₃^– → Pb²⁺ + 2 NO₃^– + Hg⁰↓
Pb⁰ + Hg²⁺ → Pb²⁺ + Hg⁰↓
c) Between copper Cu and a solution of lead nitrate Pb (NO3) 2, the reaction is impossible, because copper in the series of metal activity is to the right of lead: copper metal is less active than lead.