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NCERT Class 10 Science Acids, Bases and Salts: In-text questions (page 28) Solutions
AI-written, checked on 23 Oct 2026
Solutions written by Shishya, checked — not the board's official answers
Step-by-step working for every question of In-text questions (page 28) in NCERT's Class 10 Science book, chapter “Acids, Bases and Salts”, written by Shishya. Each question is in our own short words; open the NCERT chapter for the exact wording and figures.
How these were checked: the solutions were drafted with AI and then read and corrected on 23 Oct 2026. Every numerical final answer is recomputed from the question's own numbers by a calculator check that runs before each release; proofs and explanations were read, not machine-checked. The NCERT textbook is the authority — if something here disagrees with it, follow the book.
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In-text (page 28) Q1
Solution A has pH 6 and solution B has pH 8. Which has more hydrogen ions? Which is acidic and which is basic?
- The pH scale measures the concentration of hydrogen ions in a solution.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- A lower pH value indicates a higher concentration of hydrogen ions.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- Solution A has a pH of 6, which is lower than the pH of Solution B.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- Therefore, Solution A contains more hydrogen ions than Solution B.
- Any solution with a pH less than 7 is considered acidic.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- Solution A has a pH of 6, so it is acidic.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- Any solution with a pH greater than 7 is considered basic.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- Solution B has a pH of 8, so it is basic.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
Answer: Solution A has more hydrogen ions; Solution A is acidic and Solution B is basic.
- The pH scale measures the concentration of hydrogen ions in a solution.
In-text (page 28) Q2
How does the concentration of H⁺(aq) ions affect the nature of a solution?
- The concentration of H⁺(aq) ions determines whether a solution is acidic or basic.
- If the concentration of H⁺(aq) ions is greater than 10⁻⁷ mol/L, the solution is acidic.
- If the concentration of H⁺(aq) ions is less than 10⁻⁷ mol/L, the solution is basic.
- If the concentration of H⁺(aq) ions is exactly 10⁻⁷ mol/L, the solution is neutral.
Answer: Higher H⁺(aq) concentration makes the solution acidic, lower concentration makes it basic, and equal concentration of H⁺ and OH⁻ makes it neutral.
In-text (page 28) Q3
Do basic solutions also have H⁺(aq) ions? If yes, why are they basic?
- Yes, basic solutions do contain H⁺(aq) ions.
- This is because water itself undergoes self-ionization to produce both H⁺ and OH⁻ ions.
- In a basic solution, the concentration of hydroxide ions, OH⁻(aq), is much higher than the concentration of hydrogen ions, H⁺(aq).
- The presence of a higher concentration of OH⁻ ions compared to H⁺ ions is what makes the solution basic.
Answer: Yes, basic solutions have H⁺(aq) ions, but they are basic because the concentration of OH⁻(aq) ions is greater than that of H⁺(aq) ions.
In-text (page 28) Q4
Under what soil condition would a farmer treat the soil with quick lime, slaked lime or chalk?
- Farmers treat soil with quick lime, slaked lime, or chalk when the soil is too acidic.
- Acidic soil has a low pH value, which can harm plant growth and reduce crop yield.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- Quick lime (calcium oxide) and slaked lime (calcium hydroxide) are basic in nature.
- Chalk is a form of calcium carbonate, which is also a base.
- Adding these basic substances to acidic soil neutralizes the excess acid.
why?
An acid and a base react to give a salt and water (neutralisation): the H⁺ ions of the acid and the OH⁻ ions of the base join to form water.
- This process raises the pH of the soil to a suitable level for agriculture.
why?
pH below 7 is acidic, 7 is neutral and above 7 is basic; the lower the pH, the more hydrogen ions in the solution.
- The treatment makes the soil less acidic and more fertile for growing crops.
Answer: A farmer treats the soil with quick lime, slaked lime, or chalk when the soil is too acidic.
Other exercises in this chapter
- In-text questions (page 22) — 3 questions
- In-text questions (page 25) — 6 questions
- In-text questions (page 33) — 5 questions
- End-of-chapter exercises — 15 questions
← Acids, Bases and Salts: notes, practice and all exercises
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