NCERT Class 10 Science — Which of the following substances

Q: Which of the following substances has a pH value closest to 7 at room temperature?

Correct Option: B Pure water is a neutral substance and has a pH value of exactly 7 at 25°C. The pH scale ranges from 0 to 14, where values less than 7 indicate acidic nature, values greater than 7 indicate basic (alkaline) nature, and exactly 7 represents neutrality. Lemon juice is acidic (pH 2), soap solution is basic (pH 10), and stomach acid is highly acidic (pH 1.5). Therefore, pure water is the only neutral substance among the options.

NCERT · Class 10 · Science · Acids, Bases and SaltsWhich of the following substances has a pH value closest to 7 at room temperature?

Step-by-Step Solution

Correct Option: B

Pure water is a neutral substance and has a pH value of exactly 7 at 25°C. The pH scale ranges from 0 to 14, where values less than 7 indicate acidic nature, values greater than 7 indicate basic (alkaline) nature, and exactly 7 represents neutrality. Lemon juice is acidic (pH ~2), soap solution is basic (pH ~10), and stomach acid is highly acidic (pH ~1.5). Therefore, pure water is the only neutral substance among the options.

Detailed Options Breakdown

Option : Lemon juice

Incorrect choice. This distractor represents a common misunderstanding of the core principles of Acids, Bases and Salts.

Option 1: Pure water (Correct Answer)

Correct choice. Refer to the step-by-step verified solution guidelines above for details.

Option 2: Soap solution

Incorrect choice. This distractor represents a common misunderstanding of the core principles of Acids, Bases and Salts.

Option 3: Stomach acid

Incorrect choice. This distractor represents a common misunderstanding of the core principles of Acids, Bases and Salts.

💡 Study Guide: This question tests core syllabus concepts from Acids, Bases and Salts. For formulas, key summaries, and mock exam reference guides, read the full Acids, Bases and Salts Revision Notes.

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