Common Acids and Alkalis

Question 1

Name common acids found in homes, foods, and personal products.

Answer 1

• Vinegar
• Lemon
• Body lotions
• Hair conditioners
• Toilet cleaner
• Aspirin

Question 2

List acids used in school laboratories.

Answer 2

• Hydrochloric acid
• Sulphuric acid
• Nitric acid

Question 3

Describe the properties of acids.

Answer 3

• Sour taste
• Can conduct electricity
• React with alkalis
• React with metals to form hydrogen gas

Question 4

Explain the uses of acids.

Answer 4

• Preserving food by preventing microorganism growth
• Removing stains as cleaning agents
• Making industrial chemicals like fertilizers, dyes, and paints

Question 5

Identify common household alkalis.

Answer 5

• Glass cleaners
• Kitchen cleaners
• Drain cleaners
• Baking soda
• Toothpaste
• Soap

Question 6

List alkalis used in school laboratories.

Answer 6

• Sodium hydroxide
• Ammonia solution
• Calcium hydroxide (limewater)

Question 7

Describe the properties of alkalis.

Answer 7

• Bitter taste
• Slippery feel
• Can conduct electricity
• React with acids

Question 8

Explain the uses of alkalis.

Answer 8

• Removing grease
• Cleaning (e.g., ammonia in kitchen and glass cleaners)
• Making industrial chemicals like batteries (potassium hydroxide)

Question 9

What safety precautions should be taken when handling acids and alkalis in the laboratory?

Answer 9

• Read hazard warning labels
• Wear safety goggles and gloves
• Pour waste into appropriate bottles
• Wash hands thoroughly after experiments

Question 10

Describe the steps to take if acids or alkalis come into contact with skin or eyes.

Answer 10

• Wash affected area under slow running water for at least 10 minutes
• Remove contaminated clothing
• Wash eyes with eye wash bottle for at least 10 minutes
• Call an ambulance for serious injuries

Question 11

How does litmus indicator work?

Answer 11

Litmus solution and paper turn blue in alkaline conditions and red in acidic conditions.

Question 12

What is a universal indicator?

Answer 12

A mixture of several indicators that shows a range of colors depending on the pH of the solution, available as a solution or pH paper.

Question 13

Explain the pH scale.

Answer 13

A scale from 0 to 14 that measures acidity or alkalinity; lower pH indicates acidity, higher pH indicates alkalinity, pH 7 is neutral.

Question 14

What does a pH value of 7 signify?

Answer 14

The solution is neutral.

Question 15

Describe a pH meter.

Answer 15

A device with a probe connected to a digital display used to measure the pH value of a solution, often with a pH sensor and data-logger.

Question 16

What is the purpose of an er system in monitoring solutions?

Answer 16

It helps monitor the change in pH value of a solution.

Question 17

Describe the process of neutralization.

Answer 17

Neutralization is the chemical reaction of mixing acids and alkalis together, which can change the acidity or alkalinity of a solution, resulting in a change in pH value.

Question 18

Identify the reactants involved in a neutralization reaction.

Answer 18

The reactants are substances that take part in the reaction, such as acid and alkali.

Question 19

Identify the products formed during neutralization.

Answer 19

The products are substances formed from the reaction, such as salt and water.

Question 20

Write the general chemical equation for neutralization.

Answer 20

Acid + alkali → salt + water.

Question 21

What is released during the process of neutralization?

Answer 21

Heat is given out during neutralization.

Question 22

Does mass change during neutralization?

Answer 22

No, mass is conserved in neutralization.

Question 23

Give an example of a neutralization reaction.

Answer 23

Hydrochloric acid + sodium hydroxide → sodium chloride + water.

Question 24

Explain how neutralization is used to prevent tooth decay.

Answer 24

Brushing teeth with slightly alkaline toothpaste neutralizes acids produced by bacteria in the mouth, which can cause tooth decay. Chewing sugar-free gum stimulates saliva, which is alkaline and neutralizes mouth acids.

Question 25

Describe how neutralization helps relieve stomach upset.

Answer 25

Antacids containing alkalis neutralize excess hydrochloric acid in the stomach, reducing burning sensations caused by too much acid.

Question 26

How are acids and alkalis used to treat insect stings or bites?

Answer 26

The treatment involves neutralizing the acids or alkalis present in the sting or bite area.

Question 27

Explain the importance of neutralization in industrial waste management.

Answer 27

Industrial waste containing acids or alkalis can cause water pollution if discharged untreated. Neutralization with alkalis or acids helps to treat the waste before disposal.

Question 28

Describe how pH regulation is achieved in soil.

Answer 28

If soil is too acidic, farmers add slaked lime (calcium hydroxide) to neutralize it. If too alkaline, sulfur is added to convert to sulfuric acid, balancing the pH for better plant growth.

Question 29

What is the corrosive nature of acids?

Answer 29

Acids react with metals, often releasing hydrogen gas, which can be tested by using a burning splint.

Question 30

How can you test for the presence of hydrogen gas?

Answer 30

Use a burning splint; if hydrogen is present, it will produce a popping sound.

Question 31

Describe what happens when a burning splint is placed over a test tube containing hydrogen.

Answer 31

It burns with a 'pop' sound.

Question 32

Explain the reaction between acids and metals.

Answer 32

Acids react with metals to produce salt and hydrogen gas, causing the metal to decrease slightly in size.

Question 33

Provide an example of a reaction between hydrochloric acid and a metal.

Answer 33

Hydrochloric acid reacts with magnesium to produce magnesium chloride and hydrogen.

Question 34

Identify which metal reacts strongly with acids and which does not.

Answer 34

Magnesium reacts strongly, while copper does not react.

Question 35

Describe the reaction between acids and calcium carbonate in building materials.

Answer 35

Acids react with calcium carbonate to produce salt, carbon dioxide, and water.

Question 36

Give an example of an acid reacting with calcium carbonate.

Answer 36

Sulphuric acid reacts with calcium carbonate to produce calcium sulphate, carbon dioxide, and water.

Question 37

Define acid rain.

Answer 37

Rainwater that is slightly acidic with a pH less than 5.6, caused by pollutants like sulphur dioxide and nitrogen oxides from burning fossil fuels.

Question 38

Explain how acid rain forms.

Answer 38

Pollutants like sulphur dioxide and nitrogen oxides dissolve in water droplets in the atmosphere, forming sulphuric acid and nitric acid, which then fall as acid rain.

Question 39

Describe the environmental effects of acid rain.

Answer 39

It causes corrosion of metal objects and buildings, damages plants by destroying leaves and washing away nutrients, and harms aquatic life by increasing water acidity and dissolving harmful minerals.

Question 40

Explain how acid rain affects aquatic life.

Answer 40

It increases water acidity, making it difficult for most aquatic organisms to survive, and dissolves harmful minerals that can slow their growth and reproduction.

Question 41

Classify acids and alkalis based on their strength.

Answer 41

Strong acids include hydrochloric, sulphuric, and nitric acids; weak acids include citric, ethanoic, and carbonic acids. Strong alkalis include sodium hydroxide and potassium hydroxide; weak alkalis include ammonia solution.

Question 42

Compare the corrosiveness of strong and weak acids and alkalis.

Answer 42

Strong acids and alkalis are more corrosive than weak ones; strong acids can corrode metal, skin, and flesh, especially when concentrated.

Question 43

Describe proper handling precautions for household cleaners containing acids and alkalis.

Answer 43

Read precautions on containers, use in well-ventilated areas, never mix cleaners, and handle with care.

Question 44

Explain how to safely dilute concentrated acids or alkalis.

Answer 44

Mix them slowly with water in a well-ventilated area, add acid or alkali to water (not water to acid/alkali), stir continuously, and wear safety gear.

Question 45

List the safety precautions when diluting acids or alkalis.

Answer 45

Dilute in a well-ventilated area, wear safety goggles and gloves, add acid or alkali slowly to water, and stir continuously.

Question 46

Identify actions to avoid when handling concentrated acids or alkalis.

Answer 46

Never add water directly to concentrated acids or alkalis, never dilute with bare hands, and never inhale vapors.