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

(a) Nickel and copper walk into a bar, the bartender says, "Hey, Nick, what's up?" and Nick responds, "Not much, just feeling a little reactive today." So, he jumps into a solution of copper (II) nitrate and sparks start flying. The balanced chemical equation is:

Ni(s) + Cu(NO3)2(aq) → Ni(NO3)2(aq) + Cu(s)

(b) A solution of zinc nitrate and a solution of magnesium sulfate walk into a party together. They start mingling and suddenly, a reaction starts. The balanced chemical equation is:

Zn(NO3)2(aq) + MgSO4(aq) → ZnSO4(aq) + Mg(NO3)2(aq)

(c) Hydrochloric acid decides to throw a surprise party for gold metal. But when hydrochloric acid approaches gold with a party hat, gold says, "Sorry, I'm not in the mood for a reaction today." So, no reaction occurs. NR.

(d) Chromium metal decides to take a dip in an aqueous solution of cobalt (II) chloride. As soon as chromium touches the solution, cobalt shouts, "Hey, what do you think you're doing? Stay away from my chloride!" So, no reaction occurs. NR.

(e) Hydrogen gas starts blowing bubbles in a solution of silver nitrate. The silver ions in the solution get excited by the bubbles and yell, "Hey, come join the party!" Hydrogen happily accepts the invitation and a reaction occurs. The balanced chemical equation is:

H2(g) + 2AgNO3(aq) → 2HNO3(aq) + 2Ag(s)

(a) Nickel metal is added to a solution of copper (II) nitrate:

Ni + Cu(NO3)2 → Ni(NO3)2 + Cu

(b) A solution of zinc nitrate is added to a solution of magnesium sulfate:
Zn(NO3)2 + MgSO4 → ZnSO4 + Mg(NO3)2

(c) Hydrochloric acid is added to gold metal:
HCl + Au → NR (No reaction occurs)

(d) Chromium metal is immersed in an aqueous solution of cobalt (II) chloride:
Cr + CoCl2 → CrCl2 + Co

(e) Hydrogen gas is bubbled through a solution of silver nitrate:
H2 + 2AgNO3 → 2HNO3 + 2Ag

To write the balanced chemical equations for the given reactions, we can use the activity series (Table 4.5). The activity series lists metals in order of their reactivity, from most reactive to least reactive.

First, let's analyze each reaction and determine if a reaction will occur based on the activity series:

(a) Nickel metal is added to a solution of copper (II) nitrate.
To determine if a reaction will occur, we need to compare the reactivity of nickel and copper. According to the activity series, copper is less reactive than nickel. Therefore, a reaction will occur.
Reaction: Ni(s) + Cu(NO3)2(aq) -> Ni(NO3)2(aq) + Cu(s)

(b) A solution of zinc nitrate is added to a solution of magnesium sulfate.
Again, we need to compare the reactivity of zinc and magnesium. Zinc is more reactive than magnesium, so a reaction will occur.
Reaction: Zn(NO3)2(aq) + MgSO4(aq) -> ZnSO4(aq) + Mg(NO3)2(aq)

(c) Hydrochloric acid is added to gold metal.
The activity series does not list gold, but we know that gold is a noble metal, which means it is unreactive. Therefore, no reaction will occur.
Reaction: NR

(d) Chromium metal is immersed in an aqueous solution of cobalt (II) chloride.
Since chromium is more reactive than cobalt, a reaction will occur.
Reaction: Cr(s) + CoCl2(aq) -> CrCl2(aq) + Co(s)

(e) Hydrogen gas is bubbled through a solution of silver nitrate.
Hydrogen is less reactive than silver, so a reaction will occur.
Reaction: H2(g) + 2AgNO3(aq) -> 2Ag(s) + 2HNO3(aq)

I have provided the balanced chemical equations for the given reactions based on the activity series.

All of these follow the same rule.

A metal will displace the ion of any other metal BELOW it in the activity series.
For example:
Ni + Cu(NO3)2 ==> Cu + Ni(NO3)2
Au + HCl ==> NR (because Au is not below H).
The second one (Zn(NO3)2 + MgSO4) doesn't belong in this question since it isn't a single replacement. As it stands; however, there is no reaction.