Question

question 9 (1 point)
in the reaction $\ce{pb(no_{3})_{2}(aq) + cacl_{2}(aq) \
ightarrow ca(no_{3})_{2}(aq) + pbcl_{2}(s)}$
which element gains electrons in the process?
\\(\circ\\) oxygen
\\(\circ\\) nitrogen
\\(\circ\\) calcium
\\(\circ\\) aluminum
\\(\circ\\) no element gains electrons

Explanation:

To determine which element gains electrons, we first analyze the oxidation states of each element in the reactants and products.

• For \( \text{Pb(NO}_3\text{)}_2 \) (aq): The oxidation state of \( \text{Pb} \) is \( +2 \), \( \text{N} \) in \( \text{NO}_3^- \) is \( +5 \), \( \text{O} \) is \( -2 \).
• For \( \text{CaCl}_2 \) (aq): The oxidation state of \( \text{Ca} \) is \( +2 \), \( \text{Cl} \) is \( -1 \).
• For \( \text{Ca(NO}_3\text{)}_2 \) (aq): \( \text{Ca} \) is \( +2 \), \( \text{N} \) in \( \text{NO}_3^- \) is \( +5 \), \( \text{O} \) is \( -2 \).
• For \( \text{PbCl}_2 \) (s): \( \text{Pb} \) is \( +2 \), \( \text{Cl} \) is \( -1 \).

Since the oxidation states of all elements (Pb, N, O, Ca, Cl) remain unchanged throughout the reaction, this is a double - displacement reaction (precipitation reaction) and not a redox reaction. In a redox reaction, there is a transfer of electrons (change in oxidation states), but here there is no such change. So, no element gains electrons.

Answer:

no element gains electrons