The strength of the covalent bond in `H_(2) , F_(2)` and
HF is in the order

Options

A. `H-HgtF-FgtH-F`
B. `H-FgtF-FgtH-H`
C. `H-FgtH-HgtF-F`
D. `F-FgtH-FgtF-F`

Explanation

To determine the order of the strength of the covalent bonds in H₂, F₂, and HF, we need to analyze the nature of the bonds in each of these molecules.

### Step 1: Identify the Bonds
- **H₂ (Hydrogen molecule)**: The bond in H₂ is a single bond formed between two hydrogen atoms (H-H).
- **F₂ (Fluorine molecule)**: The bond in F₂ is a single bond formed between two fluorine atoms (F-F).
- **HF (Hydrogen fluoride)**: The bond in HF is a polar covalent bond formed between hydrogen and fluorine (H-F).

### Step 2: Analyze Bond Strength
- **H-H Bond in H₂**: The H-H bond is relatively strong due to the effective overlap of the 1s orbitals from each hydrogen atom.
- **F-F Bond in F₂**: The F-F bond is weaker than the H-H bond. This is primarily due to the presence of three lone pairs of electrons on each fluorine atom, which leads to significant electron-electron repulsion. This repulsion weakens the bond.
- **H-F Bond in HF**: The H-F bond is stronger than both the H-H and F-F bonds. This is because the bond involves an sp hybridized orbital from fluorine overlapping with the 1s orbital of hydrogen, which results in a stronger bond compared to the s-s overlap in H₂.

### Step 3: Compare the Strengths
Based on the analysis:
- The F-F bond is the weakest due to lone pair repulsions.
- The H-H bond is stronger than the F-F bond.
- The H-F bond is the strongest due to the effective overlap of orbitals.

### Conclusion: Order of Bond Strength
Thus, the order of bond strength from weakest to strongest is:
**F₂ < H₂ < HF**