An alkali is defined as having a pH in what range?

• A. 0 to 6
• B. 6 to 8
• C. 8 to 14
• D. 14 to 16

Answer: (C)

An alkali is characterized by a pH value in the range of 8 to 14. This means that substances classified as alkalis are basic in nature, which means they can accept protons or donate a pair of valence electrons. In the context of the pH scale, a value below 7 indicates acidity, while a value of 7 is neutral (like pure water). Therefore, anything above 7, specifically from 8 to 14, signifies progressively stronger basicity, with 14 representing the strongest bases.

Understanding that alkalis include various hydroxides, such as sodium hydroxide and potassium hydroxide, which contribute to high pH levels aids in recognizing the importance of their alkaline nature in chemical reactions and practical applications. The incorrect options reflect either acidic or neutral pH levels that do not meet the criteria for classification as alkalis.