Question

Which of the following is a general property of an acidic solution? (a) tastes sour (b) turns litmus paper red (c) pH less than 7 (d) neutralizes a base

Short answer

All options (a), (b), (c), and (d) are correct properties of acidic solutions.

Step-by-step solution

Identify Key Characteristics of Acids

Acidic solutions exhibit several key properties. These include tasting sour, turning blue litmus paper red, having a pH less than 7, and the ability to neutralize bases.

Analyze Each Option for Acid Properties

Evaluate each option: - Option (a): "tastes sour" – This is a classic characteristic of acids. - Option (b): "turns litmus paper red" – Acids are known to turn blue litmus paper red. - Option (c): "pH less than 7" – By definition, acids have a pH lower than 7. - Option (d): "neutralizes a base" – This is a behavior associated with acids when they react with bases.

Determine Common Characteristics

Each of the provided options correctly describes a general property of acidic solutions. All options (a), (b), (c), and (d) are properties commonly attributed to acidic solutions.

Key concepts

Properties of Acids

Acids are fascinating substances with distinct characteristics that set them apart from other chemical compounds. The most notable property is their sour taste, which is a common sensory cue that a solution is acidic. For instance, lemon juice and vinegar are acidic, and their sourness is a direct result of this property.
Additionally, acids are known for their ability to turn blue litmus paper red. This is an essential tool in chemistry to quickly identify acidic solutions.
Furthermore, acids have a pH less than 7, reflecting their higher concentration of hydrogen ions (H⁺) compared to neutral substances. Lastly, when acids interact with bases, they engage in a chemical reaction known as neutralization, demonstrating their ability to counteract basic properties. Each of these attributes helps chemists and scientists identify, categorize, and utilize acids in various applications.

Litmus Test

The litmus test is a quick and easy method for determining whether a solution is acidic or basic. In chemistry, litmus paper is a tool made from naturally occurring dyes that change color in response to acidity or alkalinity.
When blue litmus paper comes into contact with an acid, it turns red. This color change occurs because the hydrogen ions in the acid react with the dye in the litmus paper, triggering a change in its molecular structure and thus its color.
The simplicity and speed of the litmus test make it an invaluable initial screening tool. However, for precise measurements, other methods like pH meters or titration might be used. Still, the litmus test remains a staple in laboratories for its ability to quickly affirm or deny the acidic nature of a substance.

pH Scale

The pH scale is a crucial concept in understanding acidity and alkalinity. Ranging from 0 to 14, this scale quantifies the acidity or basicity of a solution. Acidic solutions have a pH value less than 7; the lower the pH, the stronger the acid.
The scale is logarithmic, meaning each whole pH value below 7 is ten times more acidic than the next higher value. For instance, a solution with pH 4 is ten times more acidic than one with pH 5. This log-based scale allows for easy comparison of acidity levels, giving us insight into how concentrated the hydrogen ions are in a solution.
A pH of 7 is considered neutral, typically represented by pure water. Understanding where a substance falls on the pH scale helps chemists to predict its behavior in reactions and its potential interactions with other compounds.

Acid-Base Neutralization

Acid-base neutralization is a chemical reaction that occurs when an acid and a base come into contact. During this process, the acid donates protons (H⁺ ions), and the base provides hydroxide ions (OH⁻).
These ions combine to form water (H₂O) and often result in the formation of salt. For example, when hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), they produce water and sodium chloride (table salt). This reaction can be represented by the equation: \[ \text{HCl} + \text{NaOH} \rightarrow \text{H}_2\text{O} + \text{NaCl} \]
This neutralization process is fundamental in chemistry for balancing pH levels, making it a vital reaction in everything from industrial processes to digestion in the human body. Understanding how neutralization works allows us to manipulate solutions to reach desired pH levels for various applications.