Question

The O-H bond length in \( H_2O \) in gas phase is

• A. 95.7 pm
• B. 90.2 pm
• C. 104.5 pm
• D. 115.5 pm

Hint:

In molecular structures, bond lengths can vary depending on the phase of the substance. Always refer to standard tables for the exact bond length values in different phases.

Answer 1

The Correct Option is A

The O-H bond length in water molecules in the gas phase is well known to be approximately 95.7 pm (picometers).
Thus, the correct bond length is \( \boxed{95.7} \, \text{pm} \).

Answer 2

Step 1: Understand the O–H bond length in water.
The bond length between oxygen and hydrogen atoms in a water molecule depends on the phase (gas or liquid) due to intermolecular interactions.

Step 2: Bond length in gas phase.
- In the gas phase, water molecules are isolated with minimal intermolecular forces.
- This results in a shorter O–H bond length compared to the liquid phase.
- Experimental measurements show that the O–H bond length in gaseous water is approximately 95.7 pm.

Step 3: Conclusion.
Therefore, the O–H bond length in water vapor (gas phase) is 95.7 pm.