PMS Everyday Science 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.

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.

Bleaching powder releases chlorine-containing disinfecting agents.
It is used in water treatment and bleaching.

Chlorine in controlled amounts disinfects water.
It reduces disease-causing bacteria and viruses.

Calcium and magnesium ions cause hardness.
Hard water forms scale and reduces soap lather.

Hardness ions react with soap molecules.
The insoluble products waste soap and reduce lather.

Temporary hardness is caused mainly by bicarbonates.
Boiling converts them into insoluble precipitates.