Question

The reaction of an acid with a carbonate or hydrogen carbonate gives what three products?

Short answer

The reaction of an acid with a carbonate or bicarbonate produces salt, carbon dioxide, and water.

Step-by-step solution

Identify the Reactants

Acids typically react with carbonates ( ext{CO}_3^{2-}) or hydrogen carbonates ( ext{HCO}_3^{-}). When forming a reaction equation, we can use a general acid, represented by ext{HxA}, where ext{A} is the anion, and a carbonate or bicarbonate such as ext{Na}_2 ext{CO}_3 (sodium carbonate) or ext{NaHCO}_3 (sodium bicarbonate).

Products of the Reaction

The general products of this reaction are a salt, carbon dioxide gas ( ext{CO}_2), and water ( ext{H}_2 ext{O}). For example, when hydrochloric acid ( ext{HCl}) reacts with sodium carbonate ( ext{Na}_2 ext{CO}_3), the products are sodium chloride ( ext{NaCl}), carbon dioxide ( ext{CO}_2), and water ( ext{H}_2 ext{O}).

Write Balanced Chemical Equation

An example of such a reaction is \[2 ext{HCl} (aq) + ext{Na}_2 ext{CO}_3 (s) ightarrow 2 ext{NaCl} (aq) + ext{CO}_2 (g) + ext{H}_2 ext{O} (l)\]. This shows that two moles of hydrochloric acid react with one mole of sodium carbonate to produce two moles of sodium chloride, one mole of carbon dioxide, and one mole of water.

Key concepts

Reaction Products

When an acid reacts with a carbonate or hydrogen carbonate, the products you get are very consistent. This consistency is crucial as it helps predict the outcome of such reactions easily. The three main products formed are:

• Salt: This is typically based on the anion from the acid used in the reaction. For instance, if the acid is hydrochloric acid (HCl), the salt produced will be a chloride like sodium chloride (\(\text{NaCl}\)).
• Carbon Dioxide (\(\text{CO}_2\)): This results from the acid liberating CO₂ gas during the reaction, and is often observed as bubbling or effervescence.
• Water (\(\text{H}_2\text{O}\)): This is the simplest product formed, involving the contribution of hydroxyl ions from the carbonate or bicarbonate.

Knowing these products not only helps in writing chemical equations but also in understanding the nature of the reactions taking place.

Chemical Equations

Writing a chemical equation accurately represents what occurs during an acid-carbonate reaction. An equation guides you to understand the proportions of reactants and products involved.
For instance, when hydrochloric acid reacts with sodium carbonate, the balanced chemical equation is:
\[ 2 \text{HCl} (aq) + \text{Na}_2\text{CO}_3 (s) \rightarrow 2 \text{NaCl} (aq) + \text{CO}_2 (g) + \text{H}_2\text{O} (l) \]
This equation illustrates the stoichiometry, meaning each element's atoms need to balance on both sides of the equation. In our example, two moles of hydrochloric acid react with one mole of sodium carbonate to produce two moles of sodium chloride, one mole of carbon dioxide, and one mole of water.
Here are some important steps to consider when writing chemical equations:

• Identify the reactants and products clearly.
• Make sure that the number of atoms for each element is balanced on both sides.
• Use correct state symbols (like \(aq\) for aqueous, \(s\) for solid, \(g\) for gas, and \(l\) for liquid).

Following these steps ensures a clear understanding of the reaction's mechanics.

Carbonate Reactions

Carbonate reactions are quite common in chemistry, especially those involving acid-base chemistry. When a carbonate or hydrogen carbonate comes into contact with an acid, a chemical reaction occurs, resulting in the formation of new substances.
A simple example can be seen when using baking soda (a common hydrogen carbonate known as sodium bicarbonate, \(\text{NaHCO}_3\)) and vinegar (acetic acid). When these two interact, they produce carbon dioxide, water, and a salt - sodium acetate in this case.
Carbonate reactions are key to many scientific fields such as geology and environmental science. They help in understanding processes like:

• Weathering of Rocks: Carbonate minerals in rocks react with acids in rainwater, contributing to geological formations.
• Carbon Cycle: In the global carbon cycle, carbonate reactions help assess carbon dioxide levels in the atmosphere.
• Coral Reefs Formation: Coral reefs are made largely of calcium carbonate, which also involves reactions similar to carbonates.

Understanding carbonate reactions helps grasp the basic nature of chemical reactions and their broader applications.