Question

Which of the following reactions will not occur as written? Which of the following reactions will not occur as written? Sn (s) + 2AgNO3 (aq) → 2Ag (s) + Sn(NO3)2 (aq) Zn (s) + Pb(NO3)2 (aq) → Pb (s) + Zn(NO3)2 (aq) Co (s) + 2HI (aq) → H2 (g) + CoI2 (aq) Mg (s) + Ca(OH)2 (aq) → Ca (s) + Mg(OH)2 (aq) Co (s) + 2AgCl (aq) → 2Ag (s) + CoCl2 (aq)

Answer 1

Answer: Option (4) is the correct answer.

Explanation:

According to the reactivity series, a more reactive metal has the ability to replace a less reactive metal in a chemical reaction.

It is known that calcium is more reactive than magnesium. So, in a chemical reaction magnesium can never replace calcium.

For example, $Mg(s) + Ca(OH)_2(aq) \rightarrow Ca(s) + Mg(OH)_2(aq)$

Therefore, this given reaction is not possible. But rest all given reactions are possible.

Thus, we can conclude that out of the given options $Mg(s) + Ca(OH)_2(aq) \rightarrow Ca(s) + Mg(OH)_2(aq)$ reaction will not occur as written.