AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
(c) Sodium hydroxide solution
Sodium hydroxide (NaOH) is a base that produces OH⁻ ions in solution. Bases have pH greater than 7, while lemon juice, vinegar, and hydrochloric acid are all acids with pH less than 7.
Source: Chapter 2, Section 2.3
The pH scale runs from 0–14: acids have pH < 7, neutral substances = 7, and bases (alkalis) have pH > 7. NaOH is a strong base, so its pH is well above 7. Lemon juice, vinegar (acetic acid), and HCl are all acidic (pH < 7). Examiners expect you to recall that bases/alkalis have pH > 7.