PMS MCQs

Carbon dioxide does not support combustion and is nonconductive.
It can displace oxygen around a fire.

Acid-carbonate reactions form a salt, water, and carbon dioxide.
The gas causes visible bubbling.

Rusting is an oxidation process requiring oxygen and moisture.
It weakens exposed iron over time.

Baking soda is sodium hydrogen carbonate, NaHCO₃.
It releases carbon dioxide when heated or mixed with acid.

Galvanization covers iron or steel with zinc.
The coating blocks moisture and can protect sacrificially.

The reaction produces carbon dioxide gas.
Gas bubbles become trapped and expand during heating.

Paint forms a protective barrier.
This slows the electrochemical reactions that cause rust.

Corrosion involves chemical or electrochemical reactions.
Rusting is a common example involving iron.

Acids donate protons in chemical reactions.
In water, they increase hydrogen-ion concentration.

Bases accept protons according to Brønsted-Lowry theory.
Many aqueous bases produce hydroxide ions.

pH values below 7 indicate acidity.
A pH of 3 is distinctly acidic.

pH values above 7 indicate basicity.
A pH of 10 is alkaline.