The incorrect statement about acids is

Options

A. they give `H^(+)` ion in water
B. they are sour in taste
C. they turn blue litmus red
D. they give pink colour with phenolphthalein.

Explanation

To determine the incorrect statement about acids, let's analyze the properties and definitions of acids step by step.

### Step 1: Understand the Definition of Acids
According to the Arrhenius theory, acids are defined as substances that, when dissolved in water, release hydrogen ions (H⁺). This means that any compound that produces H⁺ ions in an aqueous solution is considered an acid.

**Hint:** Remember that the release of H⁺ ions is a key characteristic of acids according to the Arrhenius theory.

### Step 2: Analyze the Taste of Acids
Acids are known to have a sour taste. This is a common property of many acids, such as citric acid in lemons or acetic acid in vinegar.

**Hint:** Think of common acidic substances you encounter in daily life that have a sour flavor.

### Step 3: Corrosiveness of Acids
Acids can corrode materials, especially metals. This property is significant in understanding how acids react with various substances.

**Hint:** Consider how acids can affect different materials, such as metals or skin.

### Step 4: Use of Indicators
Indicators are substances that change color in response to the acidity or basicity of a solution. Litmus paper is a common natural indicator used to test for acidity.

- Blue litmus paper turns red in acidic solutions.
- Red litmus paper does not change color in acidic solutions.

**Hint:** Recall how litmus paper works and the color changes associated with acidic and basic solutions.

### Step 5: Understanding Phenolphthalein
Phenolphthalein is a synthetic indicator. In acidic solutions, phenolphthalein remains colorless, while in basic solutions, it turns pink. This is a critical point to remember when identifying the properties of acids.

**Hint:** Focus on the color changes of phenolphthalein in different pH environments.

### Conclusion
Based on the analysis, the incorrect statement about acids is that they give pink color with phenolphthalein. Instead, acidic solutions remain colorless when phenolphthalein is added.

### Final Answer
The incorrect statement about acids is: "Acids give pink color with phenolphthalein."