Pakistan MCQs

Common table salt is sodium chloride.
It consists of sodium and chloride ions.

Most common combustion reactions require oxygen.
Removing oxygen can extinguish a fire.

Complete combustion of carbon forms carbon dioxide.
Limited oxygen may instead produce carbon monoxide.

Carbon monoxide competes with oxygen for hemoglobin.
This can deprive organs of oxygen without obvious warning.

Evaporation removes water as vapor.
The dissolved salt remains behind as crystals.

Electric current measures charge passing a point per unit time.
Its SI unit is the ampere.

Distillation boils water and then condenses the vapor.
Nonvolatile salts remain in the original container.

Electric current is measured in amperes.
An ampere equals one coulomb of charge per second.

Atoms are the basic chemical units of elements.
They contain protons, neutrons, and electrons.

Voltage represents energy transferred per unit charge.
It drives current through a circuit.

Protons carry positive electric charge.
They are located in the atomic nucleus.

Resistance is measured in ohms.
It describes opposition to electric current.