Question

What factors qualify a compound as a salt? Specify which of the following compounds are salts: \(\mathrm{CH}_{4}\) \(\mathrm{NaF}, \mathrm{NaOH}, \mathrm{CaO}, \mathrm{BaSO}_{4}, \mathrm{HNO}_{3}, \mathrm{NH}_{3}, \mathrm{KBr} ?\)

Short answer

Sodium Fluoride (NaF), Barium Sulphate (BaSO4) and Potassium Bromide (KBr) are the salts from the given list of compounds. A compound is a salt if it is made from the neutralization reaction of an acid and a base, and is composed of cations (such as Na, Ba, K) and anions (like F, SO4, Br).

Step-by-step solution

Define a Salt

A salt is a compound resulting from the neutralization reaction of an acid and a base. They are composed of cations (positively charged ions) and anions (negatively charged ions) and can be produced by a reaction from an acid and a base. The components of salts are usually in a 1:1 ratio.

Identify Cations and Anions

From the compounds given, list and identify which of them contain a cation and an anion. This is achieved by having knowledge or researching on the ionic state of the individual elements of the compound.

Identify the Salts

From the compounds investigated in step 2, ascertain which of them are salts. These would be the compounds that consist of a cation and an anion. Sodium Fluoride (NaF) is a salt as it has the cation Sodium (Na) and anion Fluoride (F). Barium Sulphate (BaSO4) is also a salt with Barium (Ba) as the cation and the Sulphate (SO4) anion. Potassium Bromide (KBr) is the third salt, with Potassium (K) as the cation and Bromide (Br) as the anion.

Key concepts

Neutralization Reaction

A neutralization reaction is a crucial process in chemistry that results in the formation of a salt. It occurs when an acid and a base react with each other. During this reaction, the acidic and basic properties cancel each other out. This leads to the creation of water and a salt.

• Acid: Typically donates protons (\(H^+\) ions) in a chemical reaction.
• Base: Typically accepts protons and donates hydroxide ions (\(OH^-\)).

When these components mix, the \(H^+\) ions from the acid combine with the \(OH^-\) ions from the base to form water (\(H_2O\)). Meanwhile, the remaining parts of the acid and base form a salt, composed of ions.
The formula can be summed up as:\[ \text{Acid} + \text{Base} \rightarrow \text{Salt} + \text{Water} \]Understanding neutralization is essential because it illustrates how salts are formed and highlights the balancing of chemical properties within reactions.

Cations and Anions

In the world of chemistry, especially in salt chemistry, it is important to understand what cations and anions are. They are the building blocks of salts.

• Cations: These are positively charged ions. They occur when an atom loses electrons, resulting in more protons than electrons. For example, Sodium (\(Na^+\)) and Barium (\(Ba^{2+}\)) are common cations.
• Anions: These are negatively charged ions. An atom becomes an anion when it gains extra electrons, causing it to have more electrons than protons. Examples include Fluoride (\(F^-\)) and Sulfate (\(SO_4^{2-}\)).

Cations and anions are drawn to each other due to their opposing charges, forming the ionic bonds that are characteristic of salts. This attraction and bonding is the reason why salts are stable ionic compounds.

Ionic Compounds

Ionic compounds are substances formed by the electrostatic attraction between cations and anions. These compounds are significant in salt chemistry.
When ions combine to form ionic compounds, they create a structured arrangement known as an ionic lattice. In this arrangement, each cation is surrounded by anions and vice versa, maximizing the attraction and minimizing repulsion.

• Properties of Ionic Compounds:
  • Usually solid at room temperature due to strong ionic bonds.
  • High melting and boiling points compared to molecular compounds.
  • Can conduct electricity when dissolved in water, as the ions are free to move.

For example, Sodium Fluoride (\(NaF\)), Barium Sulfate (\(BaSO_4\)), and Potassium Bromide (\(KBr\)) are ionic compounds. They illustrate how the mix of specific cations and anions results in the formation of salts.