Question

Which of the following statement is incorrect for \( \mathrm{H_2O_2} \) structure?

• A. It has an open book structure
• B. Its dihedral angle is \( 180^\circ \)
• C. O–O bond length is 145.8 pm and O–H is 98.8 pm
• D. Angle between both planes is 90.2°

Hint:

Remember that \( \mathrm{H_2O_2} \) has a non-planar structure with torsional (dihedral) angle not equal to 180°.

Answer 1

The Correct Option is B

Step 1: Hydrogen peroxide \( (\mathrm{H_2O_2}) \) has a bent or skewed structure and is often described as an "open book" because the oxygen atoms and attached hydrogen atoms are not co-planar.
Step 2: In the gas phase, the molecule shows a dihedral angle of around \( 111^\circ \), and in the crystalline state, this angle is about \( 90.2^\circ \). Thus, the statement about a \( 180^\circ \) dihedral angle is incorrect.
Step 3: Bond lengths:
• O–O bond length = 145.8 pm
• O–H bond length = 98.8 pm
These are correct values and confirm options (C) and (D) are correct. Hence, option (B) is false.