Question

(a) Name three common strong acids. (b) Name three common strong bases. (c) What is a characteristic behavior of a strong acid or a strong base?

Short answer

Common strong acids: HCl, H₂SO₄, HNO₃. Common strong bases: NaOH, KOH, Ca(OH)₂. Strong acids and bases completely dissociate in water.

Step-by-step solution

Identify Common Strong Acids

Step (a): Name three common strong acids. Common strong acids include hydrochloric acid (HCl), sulfuric acid (H₂SO₄), and nitric acid (HNO₃).

Identify Common Strong Bases

Step (b): Name three common strong bases. Common strong bases include sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)₂).

Understand Characteristic Behavior

Step (c): State a characteristic behavior of strong acids and bases. Strong acids and bases completely dissociate into their ions in water. For a strong acid, such as HCl, the dissociation is represented by: \( HCl \rightarrow H^+ + Cl^- \). For a strong base, such as NaOH, the dissociation is represented by: \( NaOH \rightarrow Na^+ + OH^- \). This complete dissociation leads to the high reactivity of strong acids and bases.

Key concepts

Hydrochloric Acid

Hydrochloric acid (HCl) is one of the most common strong acids. This acid is found in the stomach, specifically in gastric juice, where it helps in digestion. The strong acid nature of HCl means it fully dissociates in water. When HCl dissolves, it separates into hydrogen ions (H⁺) and chloride ions (Cl^-). This dissociation can be written as:

\( HCl \rightarrow H^+ + Cl^- \). Properties of Hydrochloric Acid:

* HCl is a colorless solution with a sharp, pungent odor.
* It has a strong acidic pH due to the release of H⁺ ions in water.
* HCl is highly corrosive and can cause burns or irritation upon contact.
Uses:

* HCl is used in industry for large-scale production of chlorides, fertilizers, and dyes.
* It is used in the cleaning of metal surfaces and as a household cleaning agent.
* As mentioned earlier, it plays a key role in digestion by breaking down food in the stomach.

Sodium Hydroxide

Sodium hydroxide (NaOH), also known as lye or caustic soda, is a typical strong base. It is commonly used in various industries and can be found in drain cleaners. Like strong acids, strong bases also completely dissociate in water. The dissociation of NaOH in water can be written as:

\( NaOH \rightarrow Na^+ + OH^- \).

Properties of Sodium Hydroxide:

* NaOH is a white, crystalline solid at room temperature.
* It has a slippery feel and is highly alkaline due to the production of hydroxide ions (OH^-).
* It is highly reactive and can cause severe burns or damage to tissues upon contact.
Uses:

* NaOH is used in the manufacture of paper, textiles, and soaps.
* It is used in the food industry to process certain foods and in the preparation of washing and cleaning agents.
* It also plays a crucial role in water treatment and pH control systems.

Acids and Bases Dissociation

Understanding the dissociation of acids and bases is important for grasping their reactivity and behavior in solutions.

Strong Acids and Bases:

* When strong acids dissolve in water, they completely dissociate into their ions.
* For example, hydrochloric acid (HCl) dissociates as: \( HCl \rightarrow H^+ + Cl^- \).
* Strong bases, like sodium hydroxide (NaOH), also fully dissociate when dissolved: \( NaOH \rightarrow Na^+ + OH^- \).

Complete vs. Partial Dissociation:

* Complete dissociation means that in an aqueous solution, all molecules of the acid or base split into ions.
* This is different from weak acids or bases, which only partially dissociate in solution.
Implications of Complete Dissociation:

* The complete dissociation results in a higher concentration of ions in the solution.
* This high concentration of ions is what makes strong acids and bases highly reactive and gives them their characteristic properties such as electrical conductivity and pronounced pH changes.
* Because of their high reactivity, they are often used in neutralization reactions and various industrial applications.