Acids and bases worksheet 2 worksheet - Free Printable

The image you've uploaded contains a worksheet on acids and bases, including a classification task and information about the properties of acids. Let's go through Question 1 and verify or explain the classifications provided.

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✔ QUESTION 1: Classify the substances as acidic or basic, and state whether pH >7 or pH <7

We are given a table with 10 substances. The goal is to classify each as acidic or basic, and indicate whether its pH is greater than 7 (basic) or less than 7 (acidic). A pH of 7 is neutral.

Let’s evaluate each one based on general scientific knowledge:

| Substance | Classification | pH | Explanation |
|---------|----------------|-----|-------------|
| 1.1 Fanta Orange | Acidic | pH < 7 | Contains citric acid and carbonic acid (from CO₂), common in soft drinks. |
| 1.2 Lux soap | Basic | pH > 7 | Soaps are typically made from fatty acids and strong bases (like NaOH), resulting in a basic solution. |
| 1.3 Tap water | Slightly acidic or neutral | pH ≈ 6–8 | Usually slightly acidic due to dissolved CO₂ forming carbonic acid, but can vary. However, it's often considered near-neutral. Here marked as acidic, which is acceptable if local water is acidic. |
| 1.4 Colgate toothpaste | Basic | pH > 7 | Toothpastes contain fluoride and mild abrasives; many are slightly basic to help prevent tooth decay. |
| 1.5 Handy Andy | Basic | pH > 7 | A cleaning agent that often contains ammonia or other alkaline compounds. |
| 1.6 Sunlight dishwashing liquid | Basic | pH > 7 | Dish soaps are usually basic to break down grease and oils. |
| 1.7 Vitamin C | Acidic | pH < 7 | Vitamin C (ascorbic acid) is an organic acid. |
| 1.8 Blood | Basic | pH > 7 | Human blood has a normal pH of around 7.35–7.45, which is slightly basic. |
| 1.9 Tartar sauce | Acidic | pH < 7 | Contains mayonnaise and lemon juice or vinegar — both acidic. |
| 1.10 Baking powder | Acidic | pH < 7 | Wait! This needs correction. |

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❗️Important Correction: Baking Powder

- Baking powder is not acidic.
- It contains baking soda (NaHCO₃), which is basic, and an acidic component (like cream of tartar).
- When mixed with water, it produces a neutralizing reaction, but baking powder itself is generally considered slightly basic due to the bicarbonate ion.
- In fact, baking powder has a pH around 8–9, making it basic.

> 🔴 So, 1.10 Baking powder should be classified as:
> - Basic
> - pH > 7

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✔ Corrected Table:

| Substance | Acidic or Basic | pH |
|----------|------------------|-----|
| 1.1 Fanta Orange | acidic | pH < 7 |
| 1.2 Lux soap | basic | pH > 7 |
| 1.3 tap water | acidic or neutral | pH ~6–7 (often <7) |
| 1.4 Colgate toothpaste | basic | pH > 7 |
| 1.5 Handy Andy | basic | pH > 7 |
| 1.6 Sunlight dishwashing liquid | basic | pH > 7 |
| 1.7 Vitamin C | acidic | pH < 7 |
| 1.8 blood | basic | pH > 7 |
| 1.9 tartar sauce | acidic | pH < 7 |
| 1.10 baking powder | basic | pH > 7 ✔ |

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🧪 Summary of Key Concepts

#### 🔹 Acids:
- Contain hydrogen (H)
- Sour taste
- pH < 7
- Produce H⁺ ions in water
- Examples: Vinegar, lemon juice, battery acid

#### 🔹 Bases:
- Feel slippery
- Bitter taste
- pH > 7
- Produce OH⁻ ions in water
- Examples: Soap, antacids, ammonia

#### 🔹 Neutral:
- pH = 7
- Example: Distilled water

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✔ Final Answer:

The only error in your table is 1.10 Baking powder — it should be classified as basic with pH > 7, not acidic.

> ✔️ Corrected classification for baking powder:
> - Acidic or Basic: Basic
> - pH: pH > 7

All others are correctly classified based on typical values.

Let me know if you'd like a printable version or a visual pH scale chart!