Order of bond length can be given as

Options

A. `H_(2)=D_(2)=T_(2)`
B. `H_(2) lt D_(2) lt T_(2)`
C. `H_(2)gtD_(2)gtT_(2)`
D. `D_(2)ltH_(2)ltT_(2)`

Answer

To determine the order of bond lengths for the isotopes of hydrogen (H₂, D₂, and T₂), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Isotopes**:
- Hydrogen (H) has one proton and no neutrons.
- Deuterium (D) has one proton and one neutron.
- Tritium (T) has one proton and two neutrons.
- The isotopes differ in their mass due to the number of neutrons.

2. **Bond Formation**:
- All three molecules (H₂, D₂, and T₂) are diatomic and formed by the sharing of two electrons between two atoms.
- The bond length is influenced by the mass of the atoms involved.

3. **Effect of Mass on Bond Length**:
- Generally, heavier isotopes (like D and T) have slightly longer bond lengths compared to lighter isotopes (like H) due to the increased mass leading to lower vibrational frequencies.
- However, the difference in bond lengths among these isotopes is minimal.

4. **Comparing Bond Lengths**:
- The bond lengths can be summarized as follows:
- H₂ bond length: approximately 0.74 Å
- D₂ bond length: approximately 0.74 Å (slightly longer than H₂)
- T₂ bond length: approximately 0.75 Å (slightly longer than D₂)
- Therefore, the bond lengths are very close to each other.

5. **Conclusion**:
- The order of bond lengths can be given as:
- H₂ ≈ D₂ ≈ T₂
- Hence, we conclude that the bond lengths of H₂, D₂, and T₂ are almost equal.

### Final Answer:
The order of bond lengths is: H₂ ≈ D₂ ≈ T₂.