Given below are the elements and the type of hydrides formed by them. Mark the incorrect match.

Options

A. phosphorus - Molecular hydride
B. potassium - Ionic hydride
C. Vanadium - Interstital hydride
D. Nitrogen - Electron - deficient covalent hydride

Explanation

To solve the problem of identifying the incorrect match between elements and the types of hydrides they form, we will analyze each element and the corresponding hydride type step by step.

### Step-by-Step Solution:

1. **Identify the Elements and Their Hydrides**:
- We have the following elements and their respective hydrides:
- Phosphorus (P) forms PH3
- Potassium (K) forms KH
- Vanadium (V) forms VH0.56
- Nitrogen (N) forms NH3

2. **Analyze Each Match**:
- **Phosphorus (P) - PH3**:
- PH3 is a molecular hydride. It is formed by covalent bonding where phosphorus shares electrons with hydrogen. The structure has one lone pair on phosphorus, making this match correct.

- **Potassium (K) - KH**:
- KH is an ionic hydride. Potassium easily ionizes to form K+ and H-, which indicates that this hydride is ionic. This match is also correct.

- **Vanadium (V) - VH0.56**:
- VH0.56 is an interstitial hydride. In this case, hydrogen is trapped in the interstitial positions of the vanadium crystal lattice, and it is known as a non-stoichiometric hydride. This match is correct as well.

- **Nitrogen (N) - NH3**:
- NH3 is a covalent hydride, but it is described as an "electron-deficient" hydride in the question. However, NH3 has a lone pair on nitrogen and is not considered electron-deficient; rather, it is a stable molecule with a pyramidal shape. Thus, this match is incorrect.

3. **Conclusion**:
- The incorrect match is with nitrogen forming an electron-deficient hydride (NH3), as NH3 is not electron-deficient.

### Final Answer:
The incorrect match is **Nitrogen (N) - NH3**.