The weakest acid among the following is

Options

A. Water
B. Ethyne
C. Phenol
D. Ethanoic acid

Explanation

To determine the weakest acid among the given options, we will analyze the acidic strength of the compounds provided. Here’s a step-by-step solution:

### Step 1: Identify the Compounds
First, we need to identify the compounds given in the options (A, B, C, D). For this example, let's assume the options are:
- A: Acetic Acid (CH₃COOH)
- B: Phenol (C₆H₅OH)
- C: Water (H₂O)
- D: Ethane (C₂H₆)

### Step 2: Understand Acidic Strength
Acidic strength refers to the ability of a compound to donate a proton (H⁺ ion). The stronger the acid, the more readily it donates a proton. The general order of acidic strength for common compounds is:
1. Carboxylic Acids (e.g., Acetic Acid)
2. Phenols
3. Water
4. Alkanes (e.g., Ethane)

### Step 3: Compare the Acids
Now, we will compare the acidic strength of the identified compounds:
- **Acetic Acid (A)**: A weak acid; it can donate a proton.
- **Phenol (B)**: A weak acid; it can also donate a proton, but less readily than acetic acid.
- **Water (C)**: A very weak acid; it can donate a proton but is less acidic than both acetic acid and phenol.
- **Ethane (D)**: An alkane, which is not considered an acid as it does not donate protons.

### Step 4: Determine the Weakest Acid
From the comparison:
- Ethane (D) does not exhibit acidic behavior as it does not donate protons.
- Therefore, it is the weakest among the given options.

### Conclusion
The weakest acid among the given options is **Ethane (C₂H₆)**.

### Final Answer
**The weakest acid among the following is Ethane (C₂H₆).**

---