One would expect proton to have very large

Options

A. charge
B. ionisation potential
C. hydration energy
D. radius

Explanation

To solve the question regarding what one would expect a proton to have very large, we can follow these steps:

### Step 1: Understand the Definition of a Proton
A proton is a positively charged particle found in the nucleus of an atom. In the context of hydrogen, when it loses its electron, it becomes a hydrogen ion (H⁺), which is essentially a proton.

**Hint:** Remember that a proton is the nucleus of a hydrogen atom without its electron.

### Step 2: Analyze the Options Given
The options provided are:
1. Charge
2. Ionization potential
3. Hydration energy
4. Radius

**Hint:** Look at each option critically and consider the properties of protons.

### Step 3: Evaluate the Charge of a Proton
The charge of a proton is approximately \(1.6 \times 10^{-19}\) coulombs. This is a fundamental charge but not considered "very large" in the context of energy or size.

**Hint:** Consider the numerical value of the charge and compare it to other physical quantities.

### Step 4: Evaluate the Radius of a Proton
The radius of a proton is about \(0.84 - 0.87\) femtometers (\(10^{-15}\) meters). This is also a very small value, so we cannot say that the radius is very large.

**Hint:** Think about the scale of atomic and subatomic particles when considering size.

### Step 5: Evaluate the Ionization Potential of a Proton
The ionization potential refers to the energy required to remove an electron from an atom or ion. Since a proton (H⁺) has no electrons, the ionization potential is effectively zero. Therefore, it cannot be considered large.

**Hint:** Recall that ionization potential is related to the presence of electrons.

### Step 6: Evaluate the Hydration Energy of a Proton
Hydration energy is the energy released when ions are dissolved in water. It is inversely proportional to the size (or radius) of the ion. Since the radius of H⁺ is very small, it results in a very large hydration energy.

**Hint:** Remember the relationship between ionic radius and hydration energy.

### Conclusion
Based on the evaluations, the only option that can be considered "very large" in the context of a proton is its hydration energy. Therefore, the answer is:

**Hydration energy.**

### Final Answer
One would expect the hydration energy of a proton to be very large.

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