Explanation

PbCl₂ (lead(II) chloride) is ionic.

Lead(II) chloride forms an ionic lattice structure with chloride ions,

while PbCl₄ is a covalent complex.

Explanation

If two streams of protons move parallel to each other in the same direction, they repel each other. 

Protons are positively charged particles, and according to Coulomb's law, particles with the same charge repel each other.

This repulsive electrostatic force dominates between the protons, causing them to push away from each other. 

Explanation

Most people are born with 12 ribs on each side of the body, making a total of 24 ribs.

Some people are born with more than 24 ribs.

These extra ribs are called supernumerary ribs.

When people are born with less than 24 ribs,

it is called agenesis of the ribs.

Explanation

Alveoli:

Bronchioles terminate in tiny air sacs called alveoli.

These are the primary sites for gas exchange in the lungs. 

Alveolar sac:

Alveoli are clustered together to form alveolar sacs

These sacs are the functional units of the lung where oxygen and carbon dioxide exchange occurs. 

Explanation

The photoelectric effect does not occur if the frequency of the incident light is below the threshold frequency.

The threshold frequency is the minimum frequency required for the incident photons to have enough energy to eject electrons from the surface of the material.

If the frequency is below this value, no electrons are emitted, regardless of the light intensity.

Explanation

Dehydrohalogenation involves the removal of a hydrogen halide from an alkyl halide

Typically carried out in the presence of alcoholic KOH

Explanation

In NaCl, each sodium ion (Na⁺) is surrounded by six chloride ions (Cl⁻) in a cubic close-packed structure.

Therefore, the coordination number of Na in NaCl is 6.

Explanation

The order of a reaction can be fractional, whereas molecularity (the number of molecules involved in the reaction)

It is always a whole number and cannot be fractional

Explanation

A phrase is a group of words that does not give a complete sense and lacks a verb.

It is a unit of language that functions as a single unit, but does not express a complete thought.

Explanation

- The elementary charge on a single electron is -1.6 × 10⁻¹⁹ coulombs.

- It’s a fundamental physical constant.