The indicator that shows colour changes in the entire pH range is

Options

A. phenolphthalein
B. methyl orange
C. universal indicator
D. thymol blue

Answer

To determine the indicator that shows color changes across the entire pH range, we can follow these steps:

### Step 1: Understand pH Indicators
Indicators are substances that change color in response to changes in pH. Different indicators have specific pH ranges in which they change color.

### Step 2: Identify Common Indicators
Common indicators include:
- **Phenolphthalein**: Changes color in the pH range of 8.2 to 10.0.
- **Methyl Orange**: Changes color in the pH range of 3.2 to 4.4.
- **Thymol Blue**: Changes color in the pH range of 6.0 to 7.6.

### Step 3: Determine the pH Range of Each Indicator
- **Phenolphthalein**: Effective only in basic solutions (pH 8.2 to 10.0).
- **Methyl Orange**: Effective only in acidic solutions (pH 3.2 to 4.4).
- **Thymol Blue**: Effective in slightly acidic to neutral solutions (pH 6.0 to 7.6).

### Step 4: Identify an Indicator for the Entire pH Range
The question asks for an indicator that can show color changes across the entire pH range from 1 to 14.

### Step 5: Conclude with the Universal Indicator
The **Universal Indicator** is the only indicator that can show color changes throughout the entire pH range of 1 to 14. It provides a spectrum of colors corresponding to different pH values.

### Final Answer
The indicator that shows color changes in the entire pH range is the **Universal Indicator**.

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