Question

Name each of the following as an acid or base: a. \(\mathrm{H}_{2} \mathrm{SO}_{4}\) b. \(\mathrm{RbOH}\) c. \(\mathrm{Ca}(\mathrm{OH})_{2}\) d. HI

Short answer

a. Acid, b. Base, c. Base, d. Acid

Step-by-step solution

- Identify the substance type (Acid or Base)

To determine if each substance is an acid or a base, recognize the typical traits: acids usually start with 'H' and bases often end with 'OH'.

- Determine the type for \(\text{H}_2\text{SO}_4\)

\(\mathrm{H}_{2} \mathrm{SO}_{4}\) is an acid because it starts with hydrogen (H) and is known as sulfuric acid.

- Determine the type for \(\text{RbOH}\)

\(\mathrm{RbOH}\) is a base because it ends with hydroxide (OH) and is known as rubidium hydroxide.

- Determine the type for \(\text{Ca(OH)}_2\)

\(\mathrm{Ca(OH)}_{2}\) is a base because it ends with hydroxide (OH) and is known as calcium hydroxide.

- Determine the type for \(\text{HI}\)

\(\mathrm{HI}\) is an acid because it begins with hydrogen (H) and is known as hydroiodic acid.

Key concepts

Acid Properties

Acids are substances that release hydrogen ions \((\text{H}^+)\) when dissolved in water.
This means that they often start with the letter 'H' in their chemical formula.
They have unique properties such as a sour taste and ability to turn blue litmus paper red.
Acids have a pH less than 7 and are often corrosive.

• Examples: Hydrochloric acid \(\text{HCl}\), Sulfuric acid \(\text{H}_2\text{SO}_4\)
• General formula: \(\text{HA}\) where 'A' is an anion

Acid strengths vary; strong acids fully ionize in water, while weak acids only partially ionize.Hydrogen ions (\(\text{H}^+\)) are the key indicators of the strength and behavior of acids.

Base Properties

Bases are substances that release hydroxide ions \((\text{OH}^-)\) when dissolved in water.
This is why they often end with 'OH' in their chemical formula.
They possess distinct properties such as a bitter taste and slippery feel.
Bases turn red litmus paper blue and have a pH greater than 7.

• Examples: Sodium hydroxide \(\text{NaOH}\), Calcium hydroxide \(\text{Ca(OH)}_2\)
• General formula: \(\text{MOH}\) where 'M' is a metal cation

Like acids, bases also vary in strength; strong bases fully dissociate in water, while weak bases only partially dissociate.Hydroxide ions \(OH^{-}\) indicate the strength and reactivity of bases.

Chemical Nomenclature

Chemical nomenclature is the system used to name chemical substances.
Acid and base nomenclature follows specific rules:

• Acids: Binary acids (with two elements) use the prefix 'hydro-', the base name of the anion, and the suffix '-ic' followed by 'acid'. For example, HCl is hydrochloric acid.
• Oxoacids (with oxygen): Anion ending in '-ate' changes to '-ic acid' (e.g., \(\text{H}_2\text{SO}_4\) becomes sulfuric acid). Anion ending in '-ite' changes to '-ous acid' (e.g., \(\text{HClO}_2\) becomes chlorous acid).
• Bases: Named like ionic compounds. For example, \(\text{NaOH}\) is sodium hydroxide, and \(\text{Ca(OH)}_2\) is calcium hydroxide.

Proper chemical naming ensures clear communication and understanding within the scientific community.This systematic approach helps avoid confusion and ensures consistency in our descriptions of chemical reactions.

Hydroxides

Hydroxides are compounds that contain the hydroxide ion \((\text{OH}^- )\).
They are generally bases because when dissolved in water they increase the concentration of hydroxide ions.
Metal hydroxides are common bases and can be found in everyday items such as cleaning products.

• Examples include sodium hydroxide \( \text{NaOH} \), commonly known as lye, and potassium hydroxide \( \text{KOH} \), used in soap making.
• The general formula can be represented as \(\text{MOH}\), where 'M' is a metal.

These compounds can be strong or weak bases depending on their ability to dissociate in water.Some hydroxides are amphoteric, meaning they can act as both acids and bases, like aluminum hydroxide \( \text{Al(OH)}_3 \).Hydroxides play significant roles in various industrial and biological processes.