posted by rob .
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.
All of these follow the same rule.
A metal will displace the ion of any other metal BELOW it in the activity series.
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.