To balance the given chemical equation, let’s start with the unbalanced equation:
[tex]\[ \text{Al (s)} + \text{Zn(NO}_3\text{)}_2\text{ (aq)} \rightarrow \text{Al(NO}_3\text{)}_3\text{ (aq)} + \text{Zn (s)} \][/tex]
First, we identify and list the number of atoms of each element on both sides of the equation:
1. Aluminum (Al)
- Reactants: 1
- Products: _
2. Zinc (Zn)
- Reactants: 1
- Products: 1
3. Nitrate (NO)_3
- Reactants: 2
- Products: 3
To balance the equation:
1. Start by balancing the aluminum atoms. Place a coefficient of 2 in front of Al(NO_3)_3 to balance the nitrate groups:
[tex]\[ \text{Al (s)} + \text{Zn(NO}_3\text{)}_2 \rightarrow 2 \text{Al(NO}_3\text{)}_3 + \text{Zn (s)} \][/tex]
2. Now, there are 2 aluminum atoms on the product side, so place a coefficient of 2 in front of Al on the reactant side:
[tex]\[ 2 \text{Al (s)} + \text{Zn(NO}_3\text{)}_2 \rightarrow 2 \text{Al(NO}_3\text{)}_3 + \text{Zn (s)} \][/tex]
3. Balance the zinc atoms by placing a coefficient of 3 in front of Zn(NO_3)_2 and Zn:
[tex]\[ 2 \text{Al (s)} + 3 \text{Zn(NO}_3\text{)}_2 \rightarrow 2 \text{Al(NO}_3\text{)}_3 + 3 \text{Zn (s)} \][/tex]
Now, let's check if the numbers of atoms are balanced on both sides of the equation:
- Aluminum (Al): 2 atoms on both sides.
- Zinc (Zn): 3 atoms on both sides.
- Nitrate (NO)_3: (3 * 2) = 6 nitrate groups on both sides.
The equation is now balanced:
[tex]\[ 2 \text{Al (s)} + 3 \text{Zn(NO}_3\text{)}_2 \rightarrow 2 \text{Al(NO}_3\text{)}_3 + 3 \text{Zn (s)} \][/tex]
From the balanced equation, the coefficient of [tex]\( \text{Al(NO}_3\text{)}_3 \)[/tex] is [tex]\( \boxed{2} \)[/tex]. Therefore, the correct answer is:
D. 2
