Chalk which is used for writing on blackboard is made up of

A)
Potassium hydroxide
B)
Sodium bicarbonate
C)
Calcium carbonate
D)
Sodium nitrate

Correct Answer : Option (C) - Calcium carbonate



Unsourced material may be challenged and removed. A blackboard (also known as a chalkboard) is a reusable writing surface on which text or drawings are made with sticks of calcium sulfate or calcium carbonate, known, when used for this purpose, as chalk.

Published On : June 11, 2021
Category : Science and Technology