Question

1. select the net ionic equation for the reaction that occurs when sodium hydroxide and iron(iii) chloride are mixed.

no reaction occurs
3 na^{+}(aq) + 3 cl^{-}(aq) \to na_{3}cl_{3}(s)
na^{+}(aq) + cl^{-}(aq) \to nacl(s)
fe^{3+}(aq) + 3 oh^{-}(aq) \to fe(oh)_{3}(s)
fe^{3+}(aq) + oh^{-}(aq) \to feoh(s)
3 na^{+}(aq) + 3 oh^{-}(aq) + fe^{3+}(aq) + 3 cl^{-}(aq) \to 3 na^{+}(aq) + 3 cl^{-}(aq) + fe(oh)_{3}(s)

Explanation:

1. First, write the balanced molecular equation for the reaction between sodium hydroxide ($\ce{NaOH}$) and iron(III) chloride ($\ce{FeCl_3}$). The reaction is a double - displacement reaction: $\ce{3NaOH(aq) + FeCl_3(aq)

ightarrow Fe(OH)_3(s) + 3NaCl(aq)}$.

1. Then, write the complete ionic equation by dissociating all strong electrolytes (aqueous compounds) into their ions. $\ce{NaOH}$ is a strong base and $\ce{FeCl_3}$ and $\ce{NaCl}$ are strong electrolytes. So the complete ionic equation is: $\ce{3Na^{+}(aq) + 3OH^{-}(aq) + Fe^{3+}(aq) + 3Cl^{-}(aq)

ightarrow Fe(OH)_3(s) + 3Na^{+}(aq) + 3Cl^{-}(aq)}$.

1. To get the net ionic equation, we cancel out the spectator ions (ions that appear on both sides of the complete ionic equation). The spectator ions here are $\ce{Na^{+}(aq)}$ and $\ce{Cl^{-}(aq)}$. After canceling them, we are left with: $\ce{Fe^{3+}(aq) + 3OH^{-}(aq)

ightarrow Fe(OH)_3(s)}$.

• Now let's analyze the options:
• "No reaction occurs" is wrong because a precipitation reaction (formation of $\ce{Fe(OH)_3}$) occurs.
• $\ce{3Na^{+}(aq) + 3Cl^{-}(aq)

ightarrow Na_3Cl_3(s)}$ is wrong. $\ce{NaCl}$ is soluble in water and does not form a solid in this reaction.

• $\ce{Na^{+}(aq) + Cl^{-}(aq)

ightarrow NaCl(s)}$ is wrong as $\ce{NaCl}$ is soluble.

• $\ce{Fe^{3+}(aq) + 3OH^{-}(aq)

ightarrow Fe(OH)_3(s)}$ matches our derived net ionic equation.

• $\ce{Fe^{3+}(aq) + OH^{-}(aq)

ightarrow FeOH(s)}$ is wrong. The formula for iron(III) hydroxide is $\ce{Fe(OH)_3}$, not $\ce{FeOH}$.

• $\ce{3Na^{+}(aq) + 3OH^{-}(aq) + Fe^{3+}(aq) + 3Cl^{-}(aq)

ightarrow 3Na^{+}(aq) + 3Cl^{-}(aq) + Fe(OH)_3(s)}$ is the complete ionic equation, not the net ionic equation.

Answer:

$\boldsymbol{\ce{Fe^{3+}(aq) + 3OH^{-}(aq)
ightarrow Fe(OH)_3(s)}}$ (the option with this equation)