The color of universal indicator solution is __________

(a) - Red

(b) - Blue

(c) - Green

(d) - Greenish-yellow

The color of a universal indicator solution varies depending on the pH level of the solution it is added to. However, if you're looking for a specific answer to the question, the color of the universal indicator solution itself is typically green when it is neutral, which corresponds to a pH of around 7. Therefore, the correct answer would be (c) - Green.

Understanding Universal Indicators

A universal indicator is a pH indicator that can change color over a wide range of pH values, providing a visual representation of acidity or alkalinity. This is particularly useful in chemistry for determining the pH of various solutions.

Color Changes Across pH Levels

Here’s how the universal indicator changes color based on pH:

• pH < 3: The solution appears red, indicating strong acidity.
• pH 4-6: The color transitions from red to orange and then to yellow, indicating increasing acidity.
• pH 7: At neutral pH, the solution is green.
• pH 8-10: The color shifts to blue, indicating a basic or alkaline solution.
• pH > 11: The solution turns purple, indicating strong alkalinity.

Practical Applications

Universal indicators are widely used in laboratories, educational settings, and even in household products to test the pH of substances. For example, if you were to add a universal indicator to lemon juice, it would turn red due to its acidic nature. Conversely, adding it to a baking soda solution would yield a blue color, reflecting its basic properties.

Why pH Matters

Understanding pH is crucial in various fields, including biology, environmental science, and medicine. For instance, the pH of soil affects plant growth, while the pH of blood is vital for maintaining homeostasis in the human body. Thus, knowing how to interpret the colors of a universal indicator can provide valuable insights into the chemical nature of different substances.

In summary, the universal indicator solution is green at neutral pH, which is a key point to remember when studying acids and bases. This knowledge not only helps in academic settings but also in practical applications across various scientific fields.