In some foam-type fire extinguishers, the reactants are `Al_2 (SO_4)_3`
(aq) and `NaHCO_3` (aq). When the extinguisher is activated, these reactants are allowed to mix producing `Al(OH)_(3(s))` and ` CO_(2(g))`.
The ` Al (OH)_3 - CO_2` foam extinguishes the fire .
Net ionic reaction of the above chemical change is :

Options

A. `Al^(3+) + HCO_3^Θ+ H_2 O rarr Al (OH)_3 + CO_2`.
B. `Al^(3+) + HCO_3^Θ + OH overset (Θ) rarr Al(OH)_3 + CO_2 +H_2 O`
C. `[Al(H_2O)_6]^(3+) HCO_3^Θ rarr Al(OH)_3 + CO_2 +H_2 O`
D. `Al_2 (SO_4)_3 + NaHCO_3 rarr Na_2 SO_4 + Al(OH)_3 + H_2O`.

Answer

To determine the net ionic reaction of the chemical change occurring in foam-type fire extinguishers involving `Al2(SO4)3` and `NaHCO3`, we will follow these steps:

### Step 1: Write the balanced molecular equation
The first step is to write the balanced molecular equation for the reaction between aluminum sulfate and sodium bicarbonate.

**Molecular Equation:**
\[ Al_2(SO_4)_3 (aq) + 6 NaHCO_3 (aq) \rightarrow 2 Al(OH)_3 (s) + 3 Na_2SO_4 (aq) + 6 CO_2 (g) + 6 H_2O (l) \]

### Step 2: Write the complete ionic equation
Next, we need to dissociate all the soluble ionic compounds into their respective ions.

**Complete Ionic Equation:**
\[ 2 Al^{3+} (aq) + 3 SO_4^{2-} (aq) + 6 Na^+ (aq) + 6 HCO_3^{-} (aq) \rightarrow 2 Al(OH)_3 (s) + 6 CO_2 (g) + 3 Na^+ (aq) + 3 SO_4^{2-} (aq) + 6 H_2O (l) \]

### Step 3: Identify and cancel the spectator ions
Spectator ions are ions that appear on both sides of the equation and do not participate in the actual reaction. In this case, the spectator ions are \( Na^+ \) and \( SO_4^{2-} \).

### Step 4: Write the net ionic equation
After canceling the spectator ions, we can write the net ionic equation, which includes only the ions and compounds that undergo a change.

**Net Ionic Equation:**
\[ 2 Al^{3+} (aq) + 6 HCO_3^{-} (aq) \rightarrow 2 Al(OH)_3 (s) + 6 CO_2 (g) + 6 H_2O (l) \]

### Summary of the Net Ionic Reaction
The net ionic reaction shows that aluminum ions react with bicarbonate ions to form solid aluminum hydroxide, carbon dioxide gas, and water.

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