18. From the following statements,

    A. For a reaction to occur spontaneously the free energy change must be negative
    B. The interaction between two nitrogen molecules in the gaseous state is predominantly electrostatic
    C. By knowing the bond energies, it is possible to deduce whether the bond is covalent or hydrogen bond
    D. Hydrophobic interactions are not important in a folded globular protein.

    Pick the combination with ALL WRONG statements.

    (1) A and B
    (2) B and C
    (3) C and D
    (4) B and D

Identifying Incorrect Chemistry Statements: Free Energy, Bonding & Hydrophobic Interactions
Understanding the Provided Statements
In chemistry, it is vital to know thermodynamics, molecular interactions, and bonding. Let’s examine the provided statements and identify which are incorrect.

Statement A: For a reaction to be spontaneous, the free energy change must be negative ✅ (Correct)

The spontaneity of a reaction is controlled by the Gibbs free energy equation:

ΔG=ΔH−TΔS

A reaction is spontaneous when ΔG is negative (exergonic reaction).

As this statement is true, it is not part of the incorrect statements.

Statement B: Two nitrogen molecules in the gaseous phase interact mainly electrostatically ❌ (Incorrect)

Nitrogen (N₂) molecules are nonpolar and engage in London dispersion forces (van der Waals interactions), not electrostatic forces.

Electrostatic interactions are between charged or polar molecules, which N₂ is not.

Therefore, this statement is false.

Statement C: Through the use of bond energies, it is possible to conclude whether the bond is hydrogen bonding or covalent ✅ (Correct)

Bond energy only tells us how strong a bond is, but not whether it‘s hydrogen bonding or covalent.

Covalent bonds share electrons, whereas hydrogen bonds are weak intermolecular forces.

This statement is false because bond energy does not classify bond type alone.

Statement D: Hydrophobic interactions are not significant in a folded globular protein ❌ (Incorrect)

Hydrophobic interactions are crucial for protein folding.

Hydrophobic residues aggregate within globular proteins, and hydrophilic residues stay on the surface.

This interaction is crucial for maintaining protein structure and stability.

Because hydrophobic interactions are significant, this statement is incorrect.

Correct Answer: (4) Statements B and D are Wrong ✅

Importance of Understanding Molecular Interactions
1. Chemical Reaction Predictions
Understanding ΔG predicts the feasibility of a reaction in thermodynamics.

2. Molecular Bonding & Stability
Material science and biology require understanding covalent, electrostatic, and van der Waals forces.

3. Protein Folding & Function
Protein folding is facilitated by hydrophobic interactions, which influence enzymatic activity, stability, and cellular function.

Conclusion
Chemistry requires knowing the nature of molecular interactions. The wrong statements here are:
✅ B: Nitrogen molecules do not interact electrostatically
✅ D: Hydrophobic interactions are important in protein folding