Question

what are acids and bases, and how do they react?
watch each term in the top box on the left with the best descriptor on the right. each descriptor may be used only once.

1. ____ acid
2. ____ base
3. ____ neutralization
4. ____ ph scale
5. ____ acid-base indicator

a. a series of numbers from 0 to 14, which describes how acidic or basic a substance is.
b. a double displacement reaction which involves mixing an acid and a base.
c. reacts with metals, tastes sour, and turns litmus paper red.
d. a substance which is one colour when added to a base and a different colour when added to an acid.
e. turns litmus blue, feels slippery, and tastes bitter.

1. you bite into an apple. it tastes very sour. use your knowledge of acids and bases to explain what type of substance must be in the apple. explain how you could test to confirm what you think.
2. explain which properties make bases good for oven and drain cleaning products.
3. classify each substance as acidic, basic, or neutral.
4. a) circle the neutralization reaction.

i) nacl + ag₂s → na₂s + agcl
ii) hcl + koh → kcl + hoh
b) explain how you know your choice is correct.
c) what are the names of the products in the neutralization reaction?

Explanation:

1. Matching Terms with Descriptors

Step1: Analyze each term

• Acid: Reacts with metals, tastes sour, and turns litmus paper red. So, 1 - C.
• Base: Turns litmus blue, feels slippery, and tastes bitter. So, 2 - E.
• Neutralization: A double - displacement reaction which involves mixing an acid and a base. So, 3 - B.
• pH scale: A series of numbers from 0 to 14, which describes how acidic or basic a substance is. So, 4 - A.
• Acid - base indicator: A substance which is one colour when added to a base and a different colour when added to an acid. So, 5 - D.

6. Apple Substance

Step1: Determine the substance type

Since the apple tastes sour, it likely contains an acid.

Step2: Test for acid

You could use blue litmus paper. If the apple (or its juice) turns blue litmus paper red, it confirms the presence of an acid.

7. Base Properties for Cleaning

Step1: Identify relevant base properties

Bases are good for oven and drain cleaning because they can react with (break down) grease and organic matter (which are often acidic or can be broken down by basic reactions). They can also help in dissolving dirt and grime due to their ability to react with various substances.

8. Substance Classification

Step1: Classify based on pH

• Blood (pH = 7.8): Basic (pH > 7).
• Tap water (pH = 7.3): Basic (pH > 7).
• Bleach (pH = 12.0): Basic (pH > 7).
• Grapefruit (pH = 2.3): Acidic (pH < 7).

9. Neutralization Reaction

Step1: Identify the neutralization reaction

a) The neutralization reaction is \(HCl + KOH
ightarrow KCl+KOH\) (II).

Step2: Explain the choice

b) A neutralization reaction is between an acid (\(HCl\)) and a base (\(KOH\)). Reaction I (\(NaCl + Ag_2S
ightarrow Na_2S + AgCl\)) is a double - displacement reaction but not between an acid and a base. Reaction II is between an acid (\(HCl\), which donates \(H^+\)) and a base (\(KOH\), which donates \(OH^-\)).

Step3: Name the products

c) The products \(KCl\) is potassium chloride and \(H_2O\) (from \(H^+\) and \(OH^-\) combining) is water.

Answer:

1. C; 2. E; 3. B; 4. A; 5. D.
2. The apple likely contains an acid. Test with blue litmus paper; if it turns red, it's an acid.
3. Bases react with grease and organic matter (can break them down), helping in cleaning.
4. a) Basic; b) Basic; c) Basic; d) Acidic.
5. a) II; b) It is between an acid (\(HCl\)) and a base (\(KOH\)); c) Potassium chloride and water.