Question

1. which of the reactions below are replacement reactions? select two correct answers. mg(s) + 2hcl(aq) → h₂(g) + mgcl₂(aq) 4al(s) + 3o₂(g) → 2al₂o₃(s) zn(s) + 2hcl(aq) → zncl₂(aq) + h₂(g) caco₃(s) → cao(s) + co₂(g) 2c₄h₁₀(g) + 13o₂(g) → 8co₂(g) + 10h₂o(g)

Explanation:

A replacement reaction is where an element replaces another in a compound, or ions swap between compounds.

1. $\text{Mg}(s) + 2\text{HCl}(aq)

ightarrow \text{H}_2(g) + \text{MgCl}_2(aq)$: Magnesium replaces hydrogen in hydrochloric acid, fitting single replacement.

1. $\text{Zn}(s) + 2\text{HCl}(aq)

ightarrow \text{ZnCl}_2(aq) + \text{H}_2(g)$: Zinc replaces hydrogen in hydrochloric acid, fitting single replacement.

1. $4\text{Al}(s) + 3\text{O}_2(g)

ightarrow 2\text{Al}_2\text{O}_3(s)$: This is a synthesis (combination) reaction, not replacement.

1. $\text{CaCO}_3(s)

ightarrow \text{CaO}(s) + \text{CO}_2(g)$: This is a decomposition reaction, not replacement.

1. $2\text{C}_4\text{H}_{10}(g) + 13\text{O}_2(g)

ightarrow 8\text{CO}_2(g) + 10\text{H}_2\text{O}(g)$: This is a combustion reaction, not replacement.

Answer:

A. $\text{Mg}(s) + 2\text{HCl}(aq)
ightarrow \text{H}_2(g) + \text{MgCl}_2(aq)$
C. $\text{Zn}(s) + 2\text{HCl}(aq)
ightarrow \text{ZnCl}_2(aq) + \text{H}_2(g)$