Everyday Science MCQs

Carbon dioxide contains one carbon atom and two oxygen atoms.
Its formula is CO₂.

The stomach secretes hydrochloric acid.
It helps activate digestive enzymes and kill many microbes.

Lightning tends to strike exposed high points and conductors.
Safer shelter is inside a substantial building or closed vehicle.

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

Vinegar contains dilute acetic acid.
This acid gives vinegar its sour taste and preservative effect.

An element contains atoms with the same number of protons.
It cannot be broken into simpler substances by ordinary chemical means.

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

Citrus fruits such as lemons and oranges contain citric acid.
It contributes to their sour taste.

A compound contains different elements chemically bonded together.
Its properties differ from those of its constituent elements.

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

Muscle cells can produce lactate during anaerobic metabolism.
This supports short-term energy production when oxygen delivery is limited.

Greater wave amplitude carries more energy.
It is generally perceived as a louder sound.