Question

Which statement about a compound on this pH scale explains why it is a base?

a. RbOH is a base because its pH is greater than 7.

b. HCl is a base because it is the lowest number on the pH scale.

c. HIO3 is a base because its pH is closest to 7.

d. HBr is a base because its pH falls between 1 and 7.

Answer 1

a. RbOH is a base because its pH is greater than 7.
This statement is correct and points at the compound being a base because an Alkali always has a pH between 7 and 14. Starting from 7 which is a neutral compound neither acidic nor alkaline, the higher the pH value, the stronger the compound is an alkali or a base. The strongest pH compounds are those that have the pH value of 14 and the weakest alkalis are those the pH value of which is closer to 7.
None of the other options fit this criteria.