Which would turn litmus paper blue?

Question

Which would turn litmus paper blue??  
A. HF  
B. KOH  
C. HNO₃  
D. C₅H₆O₃

Accepted Answer

Correct Answer: (B)KOH. 
Rationale: Potassium hydroxide (KOH) would turn litmus paper blue.Litmus paper is a common pH indicator. Blue litmus paper turns red under acidic conditions (pH &lt; 7), and red litmus paper turns blue under basic (alkaline) conditions (pH &gt; 7). A substance that turns litmus blue must be basic, meaning it increases the concentration of hydroxide ions (OH⁻) in aqueous solution.A) HF (Hydrofluoric acid)HF is an acid, albeit a weak one. In water, it partially dissociates to produce H⁺ (or H₃O⁺) ions, lowering the pH. Acids turn blue litmus paper red, not blue.B) KOH (Potassium hydroxide)KOH is a strong base. It dissociates completely in water into K⁺ ions and OH⁻ ions. The high concentration of OH⁻ raises the pH significantly above 7. A base will turn red litmus paper blue. If blue litmus paper is introduced, it will remain blue.C) HNO₃ (Nitric acid)HNO₃ is a strong, highly corrosive acid. It dissociates completely to produce H⁺ and NO₃⁻ ions, creating a very low pH. It would turn blue litmus paper red.D) C₅H₆O₃ (Levulinic acid)The molecular formula C₅H₆O₃ corresponds to levulinic acid (4-oxopentanoic acid), an organic acid containing a carboxylic acid group (-COOH). Like other acids, it donates a proton in solution, resulting in an acidic pH. It would also turn blue litmus paper red.Conclusion:The behavior of litmus paper is a classic test for acidity or basicity. Only substances with basic properties (pH &gt; 7) will cause litmus paper to appear blue. Potassium hydroxide, as a strong, ionic base, is a definitive example of such a substance.

Which would turn litmus paper blue?

A
HF

B
KOH

C
HNO₃

D
C₅H₆O₃

Potassium hydroxide (KOH) would turn litmus paper blue.

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Related Questions

Which would turn litmus paper blue?

A HF B KOH C HNO₃ D C₅H₆O₃

Potassium hydroxide (KOH) would turn litmus paper blue.

Topic Flashcards

Mini Quiz

Related Questions

A
HF

B
KOH

C
HNO₃

D
C₅H₆O₃