Which pH value represents an alkaline substance?

An alkaline substance is defined by its pH value, which indicates how basic a solution is. The pH scale ranges from 0 to 14, with values below 7 considered acidic, values at 7 considered neutral, and values above 7 considered alkaline or basic. A pH value of 7 indicates pure water, which is neutral. Therefore, a pH value of 7-8 reflects a slightly basic nature, making it alkaline.

In contrast, pH values that fall below 7 are indicative of acidic substances, while a neutral pH (7) does not reflect alkalinity. As a result, the range specified in the correct answer aligns with the definition of alkaline substances, confirming that this is the appropriate choice.