Question

Which of the following is a general property of a basic solution? (a) tastes bitter (b) turns litmus paper blue (c) pH greater than 7 (d) feels slippery

Short answer

All options (a, b, c, d) describe general properties of basic solutions.

Step-by-step solution

Understanding Basic Solutions

Basic solutions, also known as alkaline solutions, have certain characteristic properties. When dissolved in water, they produce hydroxide ions (OH⁻). They typically have a pH greater than 7, taste bitter, turn red litmus paper blue, and feel slippery to the touch. It is important to note these traits are common to basic solutions.

Checking the Options

Let's analyze each option: (a) Tastes bitter: basic solutions generally taste bitter. (b) Turns litmus paper blue: base turns red litmus paper blue. (c) pH greater than 7: by definition, bases have a pH greater than 7. (d) Feels slippery: bases feel slippery due to the saponification of oils on the skin. All these properties describe a basic solution.

Determine the General Property

Each option lists a property of basic solutions. Since the question asks for a 'general property,' it implies any characteristic commonly associated with basic solutions. Reviewing all the options, all the properties (a, b, c, d) are general properties of basic solutions.

Key concepts

pH Scale

The pH scale is a measurement system used to determine how acidic or basic a solution is. It ranges from 0 to 14, where:

• A pH value less than 7 indicates an acidic solution.
• A pH of 7 is neutral, which is the pH of pure water.
• A pH value greater than 7 indicates a basic or alkaline solution.

The pH scale is logarithmic, meaning each whole number change on the scale represents a tenfold change in acidity or basicity. For example, a solution with a pH of 8 is ten times more basic than a solution with a pH of 7.
Understanding the pH scale is crucial in evaluating the strength of acids and bases, predicting chemical behavior, and performing various scientific and industrial applications.

Litmus Test

The litmus test is a simple yet effective way to determine whether a solution is acidic or basic. It involves using litmus paper, which is treated with an indicator that changes color in response to the pH level.
There are two types of litmus papers: red and blue. Red litmus paper turns blue when exposed to a basic solution, while blue litmus paper remains blue, further confirming the basicity. On the other hand, blue litmus paper turns red when it comes into contact with an acidic solution. This quick color change offers an immediate visual cue about the nature of the solution.
However, the litmus test does not provide precise pH values. Instead, it categorizes solutions broadly as acidic or basic. Although it is not detailed, the litmus test is a popular choice for its ease of use and rapid results.

Hydroxide Ions

Hydroxide ions (OH⁻) are crucial components in determining the chemical nature of basic solutions. They form when a base dissolves in water, releasing these negatively charged ions. The presence of hydroxide ions is a key factor that gives bases their characteristic properties.
Understanding hydroxide ions helps explain why basic solutions can neutralize acids. When acids and bases react, the hydroxide ions ( OH⁻) combine with hydrogen ions ( H⁺) from the acid. This reaction forms water ( H₂O), a neutral substance. This process is called neutralization and exemplifies the balancing act between acidic and basic solutions.
The concentration of hydroxide ions influences the pH of a solution – higher concentrations lead to higher pH values, signifying stronger bases. Thus, hydroxide ions are central to the chemical behaviors and properties of bases.