Which of the following substances is the most basic?

• A. CH\(_3\)COOH
• B. NaOH
• C. HCl
• D. NH\(_4\)Cl

Answer: (B)

Verified step by step guidance

1. Identify the nature of each substance: CH\(_3\)COOH is acetic acid (a weak acid), NaOH is sodium hydroxide (a strong base), HCl is hydrochloric acid (a strong acid), and NH\(_4\)Cl is ammonium chloride (a salt that can act as a weak acid in solution).
2. Recall that basicity refers to the ability of a substance to accept protons (H\(^+\) ions) or to increase the concentration of OH\(^-\) ions in solution.
3. Recognize that strong bases like NaOH dissociate completely in water to produce OH\(^-\) ions, making the solution highly basic.
4. Understand that acids like CH\(_3\)COOH and HCl donate protons and thus are not basic; NH\(_4\)Cl, being a salt of a weak base (NH\(_3\)) and a strong acid (HCl), tends to produce a slightly acidic solution due to hydrolysis of NH\(_4^+\) ions.
5. Conclude that among the given substances, NaOH is the most basic because it fully dissociates to provide OH\(^-\) ions, increasing the pH significantly.