The reaction which disintegrates neutron is or neutron is emitted (which completes first):

Options

A. `Am_96^240 + He_2^4 to Bk_97^244 + e_(+1)^0`
B. `P_15^30 to Si_14^30 + e_(+1)^0`
C. `H_1^1 + C_6^12 to N_7^13`
D. `Al_13^27 + He_2^4 to P_15^30`

Answer

To solve the question regarding which reaction emits a neutron, we need to analyze the given nuclear reactions step by step.

### Step 1: Understand the properties of a neutron
A neutron is a subatomic particle with the following properties:
- Charge: Neutral (0)
- Atomic Number: 0
- Mass Number: 1

### Step 2: Analyze the given reactions
We need to check each reaction to see if it emits a neutron while ensuring that both atomic and mass numbers are balanced.

#### Reaction 1:
\[ \text{Am}^{240}_{96} + \text{He}^{4}_{2} \rightarrow \text{Bk}^{244}_{97} + \text{e}^{+}_{1} + \text{0}^{1} \]
- **Atomic Number Check**:
- Left Side: \( 96 + 2 = 98 \)
- Right Side: \( 97 + 1 = 98 \) (Balanced)

- **Mass Number Check**:
- Left Side: \( 240 + 4 = 244 \)
- Right Side: \( 244 + 0 = 244 \) (Balanced)

This reaction does not emit a neutron.

#### Reaction 2:
\[ \text{X}^{30}_{15} \rightarrow \text{Y}^{30}_{14} + \text{e}^{+}_{1} \]
- **Atomic Number Check**:
- Left Side: \( 15 \)
- Right Side: \( 14 + 1 = 15 \) (Balanced)

- **Mass Number Check**:
- Left Side: \( 30 \)
- Right Side: \( 30 + 0 = 30 \) (Balanced)

This reaction does not emit a neutron.

#### Reaction 3:
\[ \text{H}^{1}_{1} + \text{C}^{12}_{6} \rightarrow \text{?} \]
- **Atomic Number Check**:
- Left Side: \( 1 + 6 = 7 \)
- Right Side: Should be \( 7 \) (not provided)

- **Mass Number Check**:
- Left Side: \( 1 + 12 = 13 \)
- Right Side: Should be \( 13 \) (not provided)

This reaction does not emit a neutron.

#### Reaction 4:
\[ \text{X}^{27}_{13} + \text{He}^{4}_{2} \rightarrow \text{Y}^{30}_{15} + \text{n}^{1}_{0} \]
- **Atomic Number Check**:
- Left Side: \( 13 + 2 = 15 \)
- Right Side: \( 15 \) (Balanced)

- **Mass Number Check**:
- Left Side: \( 27 + 4 = 31 \)
- Right Side: \( 30 + 1 = 31 \) (Balanced)

This reaction emits a neutron.

### Step 3: Conclusion
From the analysis, the fourth reaction is the only one that emits a neutron. Thus, the correct answer is:

**The reaction that emits a neutron is the fourth reaction.**

---