Few questions on molecular forces

In summary, a book states that a liquid made up of non-polar molecules will not show any deflection when a charged rod is placed near it. However, an insulator will be induced and stick together when a charged object is placed near it. The concept of hydrogen bonding is an electromagnetic attractive interaction between a hydrogen atom and an electronegative atom. According to the Pauling scale, nitrogen and chlorine have the same value, but HCl does not have a hydrogen bond. This is further explained in a paper by f.c. which discusses how electrical charging induced in water droplet streams by nearby charged objects has been observed for centuries. This effect is due to a charge separation in the water droplet as it forms, induced by
  • #1
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A book said that a liquid made up of non-polar molecules shows no deflection when a charged rod is placed near the liquid
But if we place the charged object near an insulator,the insulator would be induced and therefore,they will stick together.(dont know I am correct
Another question:
A hydrogen bond is the electromagnetic attractive interaction of a hydrogen atom and an electronegative atom, such as nitrogen, oxygen or fluorine, that comes from another molecule or chemical group.
But according to the Pauling scale,N and Cl have the same value,so why HCl doesn't have hydrogen bond?
 
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  • #2
On the subject of a charged rod deflecting a stream of liquid, see the following PF thread:
https://www.physicsforums.com/showthread.php?t=559505

In particular the papers posted by f.c. (http://pubs.acs.org/doi/pdfplus/10.1021/ed077p1520) provides the following explanation:
In fact, the explanation for electrical deflection of a polar
liquid droplet stream is that the polar liquid droplets carry an
induced electrical charge. Electrical charging induced in water
droplet streams by nearby charged objects has been known
for well over two centuries, the first such observation being
attributed by Benjamin (5) to Jean Théophile Desaguilers
(1683–1744). (For a more recent review of static electrification
phenomena, see Loeb [6 ].) The effect results from a charge
separation in the water droplet as it forms, induced by the charge
on the nearby deflection device. As the droplet separates, a
fraction of the like charges repelled by the deflector statistically
remain behind in the water reservoir so that the droplet acquires
a net charge opposite to the charge on the deflector and is
attracted to it.
 

FAQ: Few questions on molecular forces

1. What are molecular forces?

Molecular forces are attractive or repulsive interactions between molecules that hold them together in a substance. These forces are responsible for the physical properties of substances such as melting point, boiling point, and viscosity.

2. What are the types of molecular forces?

The main types of molecular forces are Van der Waals forces, hydrogen bonding, and dipole-dipole interactions. Van der Waals forces are the weakest and are caused by temporary dipoles in nonpolar molecules. Hydrogen bonding is a strong dipole-dipole interaction between a hydrogen atom bonded to an electronegative element and another electronegative atom. Dipole-dipole interactions occur between polar molecules.

3. How do molecular forces affect the properties of substances?

Molecular forces play a crucial role in determining the physical properties of substances. Stronger forces result in higher melting and boiling points, as well as higher viscosity. They also affect the solubility and volatility of substances.

4. How do intermolecular forces differ from intramolecular forces?

Intramolecular forces are the bonds that hold atoms together within a molecule, while intermolecular forces are the interactions between molecules. Intramolecular forces are typically stronger than intermolecular forces.

5. How can we measure the strength of molecular forces?

The strength of molecular forces can be measured using various techniques, such as boiling point, melting point, and viscosity measurements. Additionally, spectroscopic techniques can also be used to study the interactions between molecules and determine the strength of the forces.

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