PMS MCQs

Each carbon atom bonds strongly to four others in diamond.
The rigid network resists deformation.

Polymers consist of repeating monomer units.
Many plastics, fibers, and biological molecules are polymers.

Strong polymer structures can resist decomposition.
This durability is useful but creates waste-management problems.

Steel contains iron with a controlled amount of carbon.
Other alloying elements can modify its properties.

Chromium in stainless steel creates a thin passive oxide film.
This layer limits further corrosion.

Copper conducts electricity well and can be drawn into wires.
It is also relatively resistant to corrosion.

Aluminium has a low density and good corrosion resistance.
Its alloys are widely used in aircraft.

Mercury remains liquid at typical room temperatures.
Its toxicity has reduced its use in household instruments.

Pencil cores are made mainly of graphite mixed with clay.
Graphite is a form of carbon.

In graphite, each carbon forms three bonds and leaves mobile electrons.
These electrons carry charge along the layers.

Washing soda is hydrated sodium carbonate.
It is used for cleaning and softening water.

Diamond and graphite are allotropes of carbon.
Their different structures give very different properties.