Question

select the correct answer.
a displacement reaction takes place when calcium is placed in a solution of zinc chloride. which substances will most likely be produced by the reaction?
ca + zncl₂ → ?
a. zn and cacl₂
b. cazn and cl₂
c. cacl and zncl
d. ca, zn and cl₂

Explanation:

Step1: Recall displacement reaction rules

In a single - displacement reaction, a more reactive metal displaces a less reactive metal from its compound in an aqueous solution. The reactivity series of metals is used to determine this. Calcium (Ca) is more reactive than zinc (Zn). So, calcium will displace zinc from zinc chloride ($ZnCl_2$).

The general form of a single - displacement reaction for a metal - metal chloride reaction is: $M+M'Cl_x
ightarrow MCl_x + M'$, where $M$ is the more reactive metal and $M'$ is the less reactive metal.

Step2: Apply the rule to the given reaction

For the reaction $Ca + ZnCl_2
ightarrow$?, since Ca is more reactive than Zn, Ca will displace Zn from $ZnCl_2$. The reaction will be a single - displacement reaction where Ca takes the place of Zn in $ZnCl_2$.

The chemical equation for the reaction is: $Ca+ZnCl_2 = Zn + CaCl_2$

Now let's analyze the options:

• Option A: $Zn$ and $CaCl_2$ matches the products of the single - displacement reaction we derived.
• Option B: The reaction is a single - displacement reaction, not a reaction that forms $CaZn$ and $Cl_2$. Chlorine is not liberated in this type of single - displacement reaction between a metal and a metal chloride in aqueous solution.
• Option C: The formula for calcium chloride is $CaCl_2$ (not $CaCl$) and the reaction does not form $ZnCl$. The correct products are based on the displacement of Zn by Ca.
• Option D: Calcium is the reactant and will be consumed in the reaction (it displaces Zn), so Ca will not be a product. Also, chlorine is not liberated as a product in this reaction.

Answer:

A. Zn and $CaCl_2$