Pakistan MCQs

Sublimation bypasses the liquid phase.
Dry ice changing to carbon dioxide gas is an example.

Lewis structures use lines and dots for bonds and lone pairs.
They help predict connectivity and formal charge.

Lone pairs influence shape and reactivity.
They repel bonding pairs strongly in VSEPR theory.

A single bond has order one, double bond two, and triple bond three.
Higher bond order generally means shorter, stronger bonds.

Triple bonds have higher bond order than single or double bonds.
They are usually shorter and stronger.

No single resonance structure fully represents the electron distribution.
The real structure is a resonance hybrid.

Formal charge helps compare possible Lewis structures.
Preferred structures often minimize charge separation.

Electron groups arrange to minimize repulsion.
Lone pairs and bonding regions determine molecular geometry.

Two electron groups arrange 180 degrees apart.
This minimizes repulsion.

Three electron groups arrange about 120 degrees apart.
They lie in one plane.

Four electron groups point toward tetrahedral corners.
The ideal bond angle is about 109.5 degrees.

Carbon in methane has four bonding pairs and no lone pairs.
The molecular geometry is tetrahedral.