Question

classify each chemical reaction:
reaction
hi(aq) + naoh(aq) → nai(aq) + h₂o(l)
ca(s) + f₂(g) → caf₂(s)
2h₂o₂(l) → 2h₂o(l) + o₂(g)
na₂s(aq) + fecl₂(aq) → 2nacl(aq) + fes(s)
type of reaction
( check all that apply )
combination
precipitation
combustion
acid - base
single replacement
double replacement
decomposition
combination
precipitation
combustion
acid - base
single replacement
double replacement
decomposition
combination
precipitation
combustion
acid - base
single replacement
double replacement
decomposition
combination
precipitation
combustion
acid - base
single replacement
double replacement
decomposition

Explanation:

1. HI(aq) + NaOH(aq) → NaI(aq) + H₂O(l): HI is an acid, NaOH is a base; they form salt (NaI) and water → acid-base reaction.
2. Ca(s) + F₂(g) → CaF₂(s): Two reactants combine into one product → combination reaction.
3. 2H₂O₂(l) → 2H₂O(l) + O₂(g): One reactant breaks into two products → decomposition reaction.
4. Na₂S(aq) + FeCl₂(aq) → 2NaCl(aq) + FeS(s): Ions swap (Na⁺↔Fe²⁺, S²⁻↔Cl⁻), forming solid FeS → double replacement and precipitation.

Answer:

1. HI(aq) + NaOH(aq) → NaI(aq) + H₂O(l): acid-base
2. Ca(s) + F₂(g) → CaF₂(s): combination
3. 2H₂O₂(l) → 2H₂O(l) + O₂(g): decomposition
4. Na₂S(aq) + FeCl₂(aq) → 2NaCl(aq) + FeS(s): double replacement, precipitation