Which of the following is present in pure water ?

Options

A. Ions
B. Molecules
C. Atoms
D. None of these

Explanation

To determine which of the following is present in pure water, let's analyze the options provided in the question step by step.

### Step 1: Understanding Pure Water
Pure water is defined as water that is free from any impurities or dissolved substances. It consists solely of water molecules (H₂O).

**Hint:** Remember that pure water is a compound made up of two hydrogen atoms and one oxygen atom.

### Step 2: Analyzing the Options
The question provides several options, including:
- Iron
- Molecules
- Atoms

We need to evaluate each option to see which one is present in pure water.

**Hint:** Think about the composition of water and what it means for something to be "present" in pure water.

### Step 3: Evaluating Iron
Iron is a metal and is not a component of water. Therefore, it cannot be present in pure water.

**Hint:** Consider whether the element is a part of the water molecule itself.

### Step 4: Evaluating Atoms
While water is made up of atoms (hydrogen and oxygen), the question asks about what is present in pure water. Since pure water exists primarily as H₂O molecules, referring to it as "atoms" is not accurate in this context.

**Hint:** Recall that water exists as a compound rather than individual atoms in its pure form.

### Step 5: Evaluating Molecules
Pure water consists of water molecules (H₂O). Even though water can dissociate into ions (H⁺ and OH⁻), this happens to a very minimal extent (around 1.8 x 10⁻⁹), meaning that the vast majority of water remains in its molecular form.

**Hint:** Consider the degree of dissociation of water and how it affects the presence of molecules.

### Conclusion
Based on the analysis, the correct answer is that "molecules" are present in pure water.

**Final Answer:** Molecules