Question

Fire extinguisher contain a bottle of \(\mathrm{H}_{2} \mathrm{SO}_{4}\) and: (a) \(\mathrm{MgCO}_{3}\) (b) \(\mathrm{CaCO}_{3}\) (c) \(\mathrm{NaHCO}_{3}\) (d) Any carbonate

Short answer

The best carbonate for use in a fire extinguisher is NaHCO₃ (c).

Step-by-step solution

Identify the Reactants

The problem states that a fire extinguisher contains a bottle of sulfuric acid, H₂SO₄, and a carbonate. We need to determine which specific carbonate compound can be added to the extinguisher for it to function properly.

Understand the Reaction

When an acid like H₂SO₄ reacts with carbonates, a neutralization reaction occurs, producing carbon dioxide gas, water, and a salt. This reaction can help extinguish fires by displacing oxygen or cooling the fire.

Analyze Options

Evaluate each option given: (a) MgCO₃ - Reacts with acids, forming CO₂. (b) CaCO₃ - Reacts with acids, forming CO₂. (c) NaHCO₃ - Reacts with acids, liberating CO₂ efficiently. (d) Any carbonate - General description that fits the above choices.

Choose the Best Option

Consider which compound safely generates CO₂ without excessive by-products or residue. NaHCO₃ (baking soda) is a preferable choice because it reacts efficiently with acids to produce sufficient CO₂ without leaving behind large or potentially harmful solids.

Confirm the Answer

Reactions of carbonates with acids like H₂SO₄ are generally similar, producing CO₂ gas. However, for practical use in fire extinguishers, NaHCO₃ is commonly used due to its effectiveness and safety.

Key concepts

Sulfuric Acid Reactions

Sulfuric acid, known chemically as \(\text{H}_2\text{SO}_4\), is a very strong acid widely used in various chemical processes and reactions. When it interacts with another substance, it can act as a catalyst or reactant. In the context of fire extinguishers, sulfuric acid's role is crucial.
When it reacts with carbonates, it leads to a chemical reaction that generates carbon dioxide \(\text{CO}_2\). This process falls under the category of neutralization reactions, which are essential in producing \(\text{CO}_2\) gas rapidly. The production of \(\text{CO}_2\) helps to put out fires by displacing oxygen around the fire and cooling the area. This makes the chemical reaction very important in emergency fire safety applications.

Carbonate Reactions

Carbonate compounds such as \(\text{MgCO}_3\), \(\text{CaCO}_3\), and \(\text{NaHCO}_3\) react with acids like sulfuric acid in significant ways. The general equation for the reaction of a carbonate with an acid is:
\[ \text{Carbonate} + \text{Acid} \rightarrow \text{Carbon Dioxide} + \text{Water} + \text{Salt} \]

• \(\text{MgCO}_3\) - Forms carbon dioxide and magnesium sulfate when reacting with sulfuric acid.
• \(\text{CaCO}_3\) - Produces carbon dioxide and calcium sulfate.
• \(\text{NaHCO}_3\) - Yields carbon dioxide, water, and sodium sulfate effectively.

These reactions collectively show the versatility of carbonates in reacting with acids to produce gases that are useful in fire extinguishing.

Neutralization Reactions

Neutralization reactions occur when an acid and a base react to form water and a salt. In the case of sulfuric acid and carbonates, as seen in fire extinguishers, the process includes:

• The acid, \(\text{H}_2\text{SO}_4\), neutralizing the carbonate base.
• Results in the formation of carbon dioxide and water, a key component of the extinguisher's fire-fighting ability.

In sum, neutralization reactions are central to the functioning of many fire extinguishers. They ensure that the risky potential of the fire is managed effectively by creating substances that reduce the fire's vigor without harmful residue.

Carbon Dioxide Production

Carbon dioxide \((\text{CO}_2)\) serves a crucial role in controlling and extinguishing fires. In the reactions between sulfuric acid and carbonates, \(\text{CO}_2\) is rapidly produced. This gas effectively smothers a fire by limiting its access to oxygen, effectively starving the fire of the element it needs to sustain the flame.

• Carbon dioxide is non-flammable and does not support combustion.
• As it is heavier than air, it tends to settle around the fire, creating a blanket that suffocates the flames.

The immediate and impactful generation of \(\text{CO}_2\) is fundamental to the safety offered by such extinguishers, providing an immediate response to halting the fire's progress.