Using the activity series provided, which reactants will form products?

[tex]\[ Na \ \textgreater \ Mg \ \textgreater \ Al \ \textgreater \ Mn \ \textgreater \ Zn \ \textgreater \ Cr \ \textgreater \ Fe \ \textgreater \ Cd \ \textgreater \ Co \ \textgreater \ Ni \ \textgreater \ Sn \ \textgreater \ Pb \ \textgreater \ H \ \textgreater \ Sb \ \textgreater \ Bi \ \textgreater \ Cu \ \textgreater \ Ag \][/tex]

[tex]\[ \text{1. } Ag + NaNO_3 \rightarrow \][/tex]

[tex]\[ \text{2. } Fe + Al_2O_3 \rightarrow \][/tex]

[tex]\[ \text{3. } Ni + NaCl \rightarrow \][/tex]

[tex]\[ \text{4. } Fe + Cu(NO_3)_2 \rightarrow \][/tex]

To determine which reactants will form products, we need to use the provided activity series to compare the reactivity of the metals involved in the reactions. The activity series ranks metals by their tendency to lose electrons and undergo chemical reactions. A metal can only displace another metal from a compound if it is higher in the activity series. Let's analyze each reaction step-by-step:

### Reaction: Ag + NaNO₃

1. Identify the metals involved:
- Ag (Silver)
- Na (Sodium, part of NaNO₃)

2. Compare their positions in the activity series:
- Ag is lower than Na.

Since Ag is lower than Na in the activity series, Ag cannot displace Na from NaNO₃, so no reaction will occur.

### Reaction: Fe + Al₂O₃

1. Identify the metals involved:
- Fe (Iron)
- Al (Aluminum, part of Al₂O₃)

2. Compare their positions in the activity series:
- Fe is lower than Al.

Since Fe is lower than Al in the activity series, Fe cannot displace Al from Al₂O₃, so no reaction will occur.

### Reaction: Ni + NaCl

1. Identify the metals involved:
- Ni (Nickel)
- Na (Sodium, part of NaCl)

2. Compare their positions in the activity series:
- Ni is lower than Na.

Since Ni is lower than Na in the activity series, Ni cannot displace Na from NaCl, so no reaction will occur.

### Reaction: Fe + Cu(NO₃)₂

1. Identify the metals involved:
- Fe (Iron)
- Cu (Copper, part of Cu(NO₃)₂)

2. Compare their positions in the activity series:
- Fe is higher than Cu.

Since Fe is higher than Cu in the activity series, Fe can displace Cu from Cu(NO₃)₂. Therefore, a reaction will occur, and the products will be Fe(NO₃)₂ and Cu.

### Conclusion:
After analyzing each reaction based on the activity series, we conclude:
1. [tex]$ \text{Ag} + \text{NaNO}_3 \rightarrow $[/tex] No reaction
2. [tex]$ \text{Fe} + \text{Al}_2O_3 \rightarrow $[/tex] No reaction
3. [tex]$ \text{Ni} + \text{NaCl} \rightarrow $[/tex] No reaction
4. [tex]$ \text{Fe} + \text{Cu(NO}_3\text{)}_2 \rightarrow $[/tex] Reaction occurs (products: Fe(NO₃)₂ and Cu)

Only the reaction Fe + Cu(NO₃)₂ will form products.