Using the activity series (Table 4.5 ), write balanced chemical equations for the following reactions. If no reaction occurs, simply write NR. (a) Iron metal is added to a solution of copper(II) nitrate; (b) zinc metal is added to a solution of magnesium sulfate; (c) hydrobromic acid is added to tin metal; (d) hydrogen gas is bubbled through an aqueous solution of nickel(II) chloride; (e) aluminum metal is added to a solution of cobalt(II) sulfate.

To solve this problem, we will first need to refer to the activity series for metals. The series is given in Table 4.5, but for convenience, here is a list of the metals relevant to this exercise, in decreasing order of reactivity: Aluminum (Al) > Zinc (Zn) > Iron (Fe) > Cobalt (Co) > Nickel (Ni) > Copper (Cu)

For each pair of substances given, we have to determine if a reaction occurs. A reaction will occur if the metal in its elemental form is more reactive than the metal cation in the compound. After determining if a reaction will occur or not, we can write balanced chemical equations for the reactions. (a) Iron (Fe) with Copper(II) Nitrate (Cu(NO₃)₂): Iron is more reactive than copper, so a reaction will occur between iron and copper(II) nitrate. (b) Zinc (Zn) with Magnesium Sulfate (MgSO₄): Zinc is less reactive than magnesium, so no reaction will occur between zinc and magnesium sulfate. We will write NR for this case. (c) Hydrobromic Acid (HBr) with Tin (Sn): Comparing tin with hydrogen in the series, tin is less reactive than hydrogen, so no reaction will occur between hydrobromic acid and tin metal. We will write NR for this case. (d) Hydrogen gas (H₂) with Nickel(II) Chloride (NiCl₂): Hydrogen is more reactive than nickel, so a reaction will occur between hydrogen gas and nickel(II) chloride. (e) Aluminum (Al) with Cobalt(II) Sulfate (CoSO₄): Aluminum is more reactive than cobalt, so a reaction will occur between aluminum and cobalt(II) sulfate.

Now, we write balanced chemical equations for the reactions determined in step 2. (a) Iron (Fe) with Copper(II) Nitrate (Cu(NO₃)₂): Fe(s) + Cu(NO₃)₂(aq) -> Fe(NO₃)₂(aq) + Cu(s) (b) Zinc (Zn) with Magnesium Sulfate (MgSO₄): NR (no reaction) (c) Hydrobromic Acid (HBr) with Tin (Sn): NR (no reaction) (d) Hydrogen gas (H₂) with Nickel(II) Chloride (NiCl₂): H₂(g) + 2NiCl₂(aq) -> 2HCl(aq) + 2Ni(s) (e) Aluminum (Al) with Cobalt(II) Sulfate (CoSO₄): 2Al(s) + 3CoSO₄(aq) -> Al₂(SO₄)₃(aq) + 3Co(s)