Soap is the sodium or potassium salt of: MCQ with Answer and Explanation

Soap is the sodium or potassium salt of:
A. Sulfonic acids
B. Amino acids
C. Short-chain carboxylic acids
D. Long-chain fatty acids
Answer: Option D
Solution (By JKExamLibrary)
Soap is made by saponification of triglycerides (fats/oils) which are esters of glycerol and long-chain fatty acids (e.g., stearic, palmitic, oleic). The sodium salt gives hard soap, potassium gives soft soap. The long hydrocarbon chain (hydrophobic) and carboxylate head (hydrophilic) provide cleaning action via micelle formation. Synthetic detergents are usually sodium salts of sulfonic acids or sulfate esters.

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Practice More chemistry Questions

Question #1
Vanadium(V) oxide is used as a catalyst in the manufacture of:
A. Sulphuric acid
B. Ammonia
C. Sodium hydroxide
D. Nitric acid

Correct Answer: Option A


Explanation:
V₂O₅ catalyzes the oxidation of SO₂ to SO₃ in the Contact process for sulfuric acid: 2SO₂ + O₂ ⇌ 2SO₃. Fe is used for ammonia (Haber). Pt-Rh gauze for nitric acid (Ostwald). Sodium hydroxide is made by chlor-alkali electrolysis, no catalyst needed. V₂O₅ is preferred over Pt because it is cheaper and less susceptible to poisoning by arsenic impurities.

This question belongs to: Science chemistry
Question #2
Which of the following is a basic salt?
A. NH₄Cl
B. NaNO₃
C. NaCl
D. CH₃COONa

Correct Answer: Option D


Explanation:
Sodium acetate (CH₃COONa) is a salt of weak acid (acetic acid) and strong base (NaOH). It hydrolyzes to produce OH⁻ ions: CH₃COO⁻ + H₂O ⇌ CH₃COOH + OH⁻, making the solution basic. NaCl (strong acid-strong base) neutral. NH₄Cl (strong acid-weak base) acidic. NaNO₃ neutral. Basic salts turn red litmus blue.

This question belongs to: Science chemistry
Question #3
The element with the largest atomic radius in period 3 is:
A. Ar
B. Mg
C. Na
D. Cl

Correct Answer: Option C


Explanation:
Atomic radius decreases across a period due to increasing nuclear charge. Sodium (Na) is the first element in period 3, thus it has the largest atomic radius. Argon (noble gas) has the smallest (though noble gas radii are van der Waals and larger than covalent, but still trend is decreasing). For metals, Na > Mg > Al; non-metals further smaller.

This question belongs to: Science chemistry