5. In a hydrogen bond of the type D-H…A, where D-H is a weakly acidic donor group and A is a
lone-pair-bearing acceptor atom, the D…A distance is
(1) one-and-a-half times the sum of the van Der Waals radii.
(2) equal to the sum of the van Der Waals radii.
(3) less than the sum of the van Der Waals radii.
(4) twice the sum of the van Der Waals radii.

From DNA structure to protein folding, hydrogen bonds are essential for molecular stability. The bond strength and interaction distance are important determinants of molecular properties in a hydrogen bond of the type D-H…A, where A is a lone-pair-bearing acceptor and D-H is a weakly acidic donor.

In hydrogen bonding, what is the D…A Distance?

The D…..A  is The distance between the acceptor (A) and donor (D) atoms is called a distance.

This distance is determined by several factors, including:

The acceptor and donor atoms’ electronegativity.

the degree of hydrogen bonding in a particular solvent.

Van der Waals radii are frequently used to estimate the size of the involved atoms.

Van der Waals Radii: Van der Waals radii are estimates of the effective sizes of atoms or molecules. They represent the distances at which attractive and repulsive forces between atoms are balanced. These radii help to define the boundaries of individual atoms in a molecule.

Double the sum of the Van der Waals radii is the proper distance.

The right response, out of the options provided, is 4: The D…. A  Van der Waals radii added together form a distance.

This happens as a result of:

While hydrogen bonds are shorter than purely electrostatic interactions, they are longer than covalent bonds.

This range usually contains the optimal hydrogen bond distance, guaranteeing stability and flexibility.

Although this distance can be affected by solvent conditions and molecular environments, the general pattern is consistent across various hydrogen-bonding interactions.

Why Other Choices Are Wrong

The real hydrogen bond distance is underestimated by 1.5 times the sum of the van der Waals radii.

This would be too short and prevent appropriate hydrogen bonding. It is equivalent to the sum of the van der Waals radii.

Less than the sum of the van der Waals radii: Because of their weaker intermolecular forces, hydrogen bonds are longer than van der Waals contacts.

In conclusion

The D…A Option 4 is the right response because a distance in hydrogen bonding is roughly twice the sum of van der Waals radii. Comprehending this relationship facilitates the study of biomolecular interactions, drug design, and molecular modelling.

A key component of molecular interactions, hydrogen bond distances affect everything from chemical reactivity to protein structure. Gaining a deeper understanding of these concepts can help one in a variety of scientific and medical domains.