Acids bases and salts | PPT - Free Printable

It looks like the image you've uploaded is a title slide for a presentation or study material related to Class 10 Science, specifically on the topic of Acids, Bases, and Salts. However, there is no actual question or problem visible in the image — it only contains the heading:

> Class 10
> ACIDS, BASES, SALTS
> IMPORTANT QUESTIONS AND ANSWERS

Since no specific question is provided, I can't solve a particular problem from the image.

But if you're looking for help with important questions and answers on Acids, Bases, and Salts for Class 10 (likely based on the CBSE curriculum), I can provide some commonly asked questions and their detailed explanations.

---

🔬 Important Questions & Answers: Acids, Bases, and Salts (Class 10)

#### Q1. What are acids? Give two examples.
Answer:
Acids are substances that release hydrogen ions (H⁺) when dissolved in water. They have a sour taste and turn blue litmus paper red.
Examples:
- Hydrochloric acid (HCl)
- Sulfuric acid (H₂SO₄)

---

#### Q2. What are bases? Give two examples.
Answer:
Bases are substances that release hydroxide ions (OH⁻) when dissolved in water. They have a bitter taste and turn red litmus paper blue.
Examples:
- Sodium hydroxide (NaOH)
- Calcium hydroxide (Ca(OH)₂)

---

#### Q3. Define neutralization reaction with an example.
Answer:
A neutralization reaction is a chemical reaction between an acid and a base to form salt and water.
Example:
$$
\text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O}
$$
Hydrochloric acid reacts with sodium hydroxide to form sodium chloride (salt) and water.

---

#### Q4. Why does the pH of milk change as it turns into curd?
Answer:
Milk has a pH around 6–7 (slightly acidic). When it turns into curd, lactic acid is produced by bacterial fermentation, which lowers the pH (makes it more acidic). This decrease in pH causes the milk proteins to coagulate, forming curd.

---

#### Q5. What is the role of indicators in identifying acids and bases?
Answer:
Indicators are substances that change color depending on whether they are in an acidic or basic medium.
- Litmus: Red in acid, blue in base
- Phenolphthalein: Colorless in acid, pink in base
- Methyl orange: Red in acid, yellow in base

They help determine the nature of a solution without measuring pH precisely.

---

#### Q6. How do antacids work?
Answer:
Antacids are bases (like magnesium hydroxide or aluminum hydroxide) that neutralize excess stomach acid (HCl), relieving indigestion and heartburn.
Example:
$$
\text{Mg(OH)}_2 + 2\text{HCl} \rightarrow \text{MgCl}_2 + 2\text{H}_2\text{O}
$$

---

#### Q7. Why should curd not be kept in copper vessels?
Answer:
Curd contains lactic acid, which reacts with copper metal to form toxic compounds (e.g., copper lactate), which can be harmful if consumed. It also changes the taste and may lead to health issues.

---

#### Q8. What is the common name of Na₂CO₃·10H₂O?
Answer:
The common name is washing soda.

---

#### Q9. What happens when zinc granules are added to dilute sulfuric acid? Write the balanced equation.
Answer:
Zinc reacts with dilute sulfuric acid to produce hydrogen gas and zinc sulfate.
$$
\text{Zn} + \text{H}_2\text{SO}_4 \rightarrow \text{ZnSO}_4 + \text{H}_2 \uparrow
$$

---

#### Q10. What is the difference between strong and weak acids?
Answer:
- Strong acids completely dissociate in water (e.g., HCl, HNO₃).
- Weak acids partially dissociate in water (e.g., CH₃COOH - acetic acid).

---

If you'd like, I can generate a full PDF or worksheet of these questions and answers, or help with any specific question you’re struggling with.

Let me know what kind of problem you'd like solved!