Which Of The Following Is Not A Property Of Bases

Which of the following is not a property of bases Bases are a fundamental class of chemicals that appear everywhere—from household cleaning agents to the buffering systems that keep our blood pH stable. Understanding what truly defines a base helps students avoid common pitfalls when answering multiple‑choice questions in chemistry exams. This article explores the characteristic properties of bases, highlights which statements are not true of bases, and explains why certain misconceptions arise. By the end, you’ll be able to confidently identify the incorrect property in any “which of the following is not a property of bases” question.

Introduction

When faced with a question that asks which of the following is not a property of bases, the key is to recall the defining features that separate bases from acids and other substances. Bases share a set of observable and measurable traits, but they also have clear limitations. In the sections below, we list the accepted properties, examine typical distractors found in exam questions, and provide a concise rationale for the correct answer.

Understanding Bases: A Quick Refresher

A base, according to the Brønsted‑Lowry definition, is a substance that accepts a proton (H⁺). In the Lewis sense, a base donates an electron pair. Practically, most bases encountered in introductory chemistry are aqueous solutions of metal hydroxides (e.g., NaOH, KOH) or compounds that generate hydroxide ions (OH⁻) when dissolved.

Because hydroxide ions are responsible for many of the observable behaviors, the properties of bases are often described in terms of what OH⁻ does in water.

Common Properties of Bases

Below is a checklist of the properties that are universally true for bases (especially aqueous bases). Each point is bolded for quick reference.

• Bitter taste – Unlike the sour taste of acids, bases feel bitter on the tongue (though tasting chemicals is never recommended in a lab setting).
• Slippery or soapy feel – Hydroxide ions interact with skin oils, giving a characteristic slick sensation.
• Turns red litmus paper blue – This classic test is a reliable visual indicator; bases shift red litmus to blue.
• pH greater than 7 – In aqueous solution, bases raise the pH above neutral (pH > 7).
• React with acids to form salt and water – Neutralization reactions (e.g., HCl + NaOH → NaCl + H₂O) are a hallmark of base behavior. - Conduct electricity when dissolved – The presence of mobile OH⁻ (and accompanying cations) allows aqueous bases to conduct current. - Can be strong or weak – Strong bases (e.g., NaOH) dissociate completely; weak bases (e.g., NH₃) only partially accept protons.
• Feel corrosive to skin and tissues – Concentrated bases can cause chemical burns, similar to strong acids, though the mechanism differs (saponification of fats).
• Do not donate protons – By definition, bases accept protons; they are not proton donors.

These properties form the foundation for identifying bases in both qualitative and quantitative analyses.

What Is Not a Property of Bases

Now we turn to the core of the question: which of the following is not a property of bases. Typical distractors in exam questions include statements that are true for acids, neutral substances, or are outright false. Below we examine each common option and explain why it fails to describe a base.

1. “They have a pH less than 7”

• Explanation: A pH below 7 indicates an acidic solution. Bases, by definition, raise the pH above 7. Therefore, claiming a base has a pH < 7 is incorrect.
• Why it appears: Students sometimes confuse the pH scale direction or misremember that “basic” means “low pH.”

2. “They turn blue litmus paper red”

• Explanation: Litmus paper changes color in response to pH: red litmus turns blue in base, while blue litmus turns red in acid. A base cannot turn blue litmus red.
• Why it appears: The reverse statement is a property of acids, making it a classic distractor.

3. “They taste sour”

• Explanation: Sour taste is characteristic of acids (e.g., citric acid in lemon juice). Bases taste bitter, not sour.
• Why it appears: The sour/bitter taste pair is often memorized incorrectly, leading to this false option.

4. “They are proton donors”

• Explanation: Proton donation defines an acid (Brønsted‑Lowry). Bases accept protons; they do not donate them.
• Why it appears: Confusing the acid/base roles in proton transfer reactions is a frequent source of error.

5. “They do not conduct electricity in aqueous solution”

• Explanation: Dissociated bases produce ions (OH⁻ and cations) that enable electrical conductivity. Pure, undissolved bases may not conduct, but in aqueous solution they do.
• Why it appears: The statement overlooks the ionic nature of dissolved bases.

Among these, the most common correct answer to “which of the following is not a property of bases” is “They have a pH less than 7.” This directly contradicts the fundamental definition of a base.

Example Multiple‑Choice Question

To illustrate how the concept is tested, consider the following sample item:

Which of the following is not a property of bases?
A. They taste bitter.
B. They turn red litmus paper blue.
C. They have a pH less than 7.
D. They feel slippery.

Answer: C. Explanation: Aqueous bases have a pH greater than 7; a pH below

7 indicates acidity, not basicity.

Conclusion

Bases are defined by a set of consistent chemical and physical properties: they accept protons or donate hydroxide ions, taste bitter, feel slippery, turn red litmus blue, and yield pH values above 7. Any statement suggesting bases have a pH below 7, turn blue litmus red, taste sour, donate protons, or fail to conduct electricity in solution directly contradicts these properties and is therefore incorrect. Recognizing these distinctions is essential for correctly identifying bases in both theoretical and practical contexts.