Pakistan MCQs

Moles = mass ÷ molar mass = 9 ÷ 18.
The sample therefore contains 0.5 mol.

Structural isomers connect atoms in different sequences.
They can have different physical and chemical properties.

Moles = mass ÷ molar mass = 36 ÷ 18.
The sample therefore contains 2 mol.

Stereoisomers share the same bonding sequence.
Geometric and optical isomers are major types.

Moles = mass ÷ molar mass = 22 ÷ 44.
The sample therefore contains 0.5 mol.

The pi bond prevents free rotation.
Each double-bond carbon must have two different substituents for geometric isomerism.

Moles = mass ÷ molar mass = 88 ÷ 44.
The sample therefore contains 2 mol.

Addition reactions reduce unsaturation.
Alkenes commonly undergo electrophilic addition.

Moles = mass ÷ molar mass = 29.2 ÷ 58.5.
The sample therefore contains 0.5 mol.

Substitution preserves much of the carbon skeleton.
Halogenation of alkanes is an example.

Moles = mass ÷ molar mass = 117 ÷ 58.5.
The sample therefore contains 2 mol.

Elimination often removes H and another group from adjacent atoms.
It commonly forms an alkene.