False statement is:

Options

A. Chloroform is heavier than water
B. `"CCl"_(4)` is non-flammable
C. Vinyl chloride is more reactive than allyl chloride
D. In water Br– is a good nucleophile as compared to F–

Answer

To solve the question, we need to analyze each of the given statements to identify which one is false.

### Step 1: Analyze Option 1
**Statement:** Chloroform is heavier than water.
- **Explanation:** Chloroform (CHCl3) has a higher molecular mass than water (H2O). The density of chloroform is approximately 1.48 g/cm³, while the density of water is 1 g/cm³. Therefore, this statement is true.

**Hint:** Compare the densities of chloroform and water to determine which is heavier.

### Step 2: Analyze Option 2
**Statement:** CCl4 (carbon tetrachloride) is non-flammable.
- **Explanation:** Carbon tetrachloride is indeed non-flammable and is often used in fire extinguishers. This statement is true.

**Hint:** Recall the properties of carbon tetrachloride regarding its flammability.

### Step 3: Analyze Option 3
**Statement:** Vinyl chloride is more reactive than allyl chloride.
- **Explanation:** Vinyl chloride (CH2=CHCl) has a chlorine atom that can participate in resonance, which stabilizes the molecule and makes it less reactive. Allyl chloride (CH2=CH-CH2Cl) does not have such resonance stabilization, making it more reactive. Therefore, this statement is false.

**Hint:** Consider the effects of resonance on the reactivity of compounds.

### Step 4: Analyze Option 4
**Statement:** In water, Br⁻ is a better nucleophile than F⁻.
- **Explanation:** Bromide ion (Br⁻) is indeed a better nucleophile than fluoride ion (F⁻) in polar protic solvents like water due to its larger size and lower charge density, which makes it more stable and reactive. This statement is true.

**Hint:** Think about the size and charge density of the halide ions when determining nucleophilicity.

### Conclusion
After analyzing all the options, we find that **Option 3** is the false statement. Therefore, the answer to the question is:

**Final Answer:** Option 3 is the false statement: "Vinyl chloride is more reactive than allyl chloride."