Acids (H+ furnishing) MCQs Quiz | Class 10
This Class X Science (Code 086) quiz covers Unit I: Chemical Substances – Nature and Behaviour. It specifically targets the topic of Acids (H+ furnishing), focusing on the definition in terms of H+ ions produced in aqueous solutions. Complete these 10 multiple-choice questions to test your knowledge, view your score instantly, and download the solution PDF for your records.
Understanding Acids and H+ Ions
In Class 10 Science, the definition of acids is fundamentally linked to their behavior in water. An acid is a substance which, when dissolved in water, dissociates to produce hydrogen ions (H+). However, hydrogen ions cannot exist alone; they combine with water molecules to form hydronium ions (H3O+).
Key Concepts
- Arrhenius Definition: An acid increases the concentration of H+ ions in an aqueous solution.
- Hydronium Ion Formation: H+ + H2O -> H3O+. We often write H+(aq) or H3O+(aq) to represent acid ions.
- Strong Acids: These completely ionize in water, producing a large concentration of H+ ions (e.g., HCl, H2SO4, HNO3).
- Weak Acids: These partially ionize in water, producing a low concentration of H+ ions (e.g., CH3COOH, H2CO3).
- Electrical Conductivity: Aqueous solutions of acids conduct electricity due to the presence of free mobile ions (H+ and anions).
Comparison: Strong vs Weak Acids
| Feature | Strong Acid | Weak Acid |
|---|---|---|
| Ionization | Complete (100%) | Partial (Reversible) |
| H+ Concentration | High | Low |
| Example | Hydrochloric Acid | Acetic Acid |
Quick Revision Notes
- Dry HCl gas does not change the color of dry blue litmus paper because no H+ ions are formed in the absence of water.
- Compounds like glucose and alcohol contain hydrogen but are not categorized as acids because they do not ionize to give H+ in water.
- Always add acid to water slowly with stirring for dilution, never water to acid, to prevent splashing due to the exothermic nature.
Extra Practice Questions
- Q1: What ion is responsible for the acidic property? (Ans: H+ / H3O+)
- Q2: Why does rain water conduct electricity? (Ans: Presence of acids forming ions)
- Q3: Write the ionization equation for HCl. (Ans: HCl + H2O -> H3O+ + Cl-)
- Q4: Which acid is found in vinegar? (Ans: Acetic acid)
- Q5: Is Citric acid strong or weak? (Ans: Weak)
