On the pH scale, acids fall between and bases fall between 0 1 and 5; 6 and 12
O and 6.9; 7.1 and 14
O and 6; 7 and 14
2 and 3: 8 and 9

The correct answer is - O and 6.9; 7.1 and 14

Explanation:

A measuring scale that tells about the acidity or basicity or alkaline nature of a particular object or solution is possible with the help of a pH scale that measures how acidic or basic a solution or object is.

It ranges between 0 to 14. pH less than 7 or ranging from 0.0 to 6.9 is acidic and more than 7 or from 7.1 to 14.0 is basic or alkaline in nature. A measure of the relative amount of H+ ion and OH- ions in water is pH.

1. efficient use of space

2. elimination of groundwater contamination

3. energy generation

4. lower carbon footprint