Question

Chalk is an ionic compound. Which is a property of all ionic compounds that makes chalk particularly useful for writing on a chalkboard?

a high melting point
hardness and brittleness
inability to dissolve in water
a multicolored appearance

Answer 1

The property of chalk (which is composed primarily of calcium carbonate, CaCO₃) that makes it particularly useful for writing on a chalkboard is **hardness and brittleness**. This property allows chalk to be shaped into sticks that can effectively write on surfaces, while the brittleness means it can be easily broken into smaller pieces when needed.

So, the answer is:

**hardness and brittleness**