+++++ Reactions between acids and bases

Question 1

What are the 2 most common laboratory acids and what are their chemical formulas?

Answer 1

the 2 most common laboratory acids are hydrochloric acid (HCI) and sulfuric acid (H₂SO₄).

Question 2

What are strong acids?

Answer 2

Strong acids are acids that break up (dissociate) almost completely when dissolved in water.

Question 3

What are the 2 most common laboratory bases and what are their chemical formulas?

Answer 3

the 2 most common laboratory bases are sodium hydroxide (NaOH, caustic soda) which is a strong alkaline and calcium hydroxide Ca(OH)₂.
Sodium hydroxide is very corrosive and is used to clear blocked drains

Question 4

What is lime water and what does it contain?

Answer 4

Lime water is a chemical that is used to test for carbon dioxide. It contains a base called calcium hydroxide.

Question 5

What does antiacid mean and what are they, what do they do?

Answer 5

Antiacid means against acid. Antiacids are bases that cure stomach upsets by reacting with the excess acid in the stomach.

Question 6

What is the reaction between an acid and a base called? What happens to the properties of the acid?

Answer 6

The reaction between an acid and a base is called a neutralisation reaction. The properties of an acid are counteracted or neutralised by a base.

Question 7

Give an example of a neutralisation reaction

Answer 7

Brushing your teeth with toothpaste is an example of a neutralisation reaction.
Toothpaste is a basic substance. It neutralises the acids that damage your teeth.

Question 8

What forms when an acid and a base neutralise each other? Give the chemical formula of this

Answer 8

when an acid and a base neutralise each other, salt and water are formed.
Acid + base —-> salt + water

Question 9

In science, what is salt?

Answer 9

In science, the word salt applies to many other substances

Question 10

What is the most common example of a neutralisation reaction? Give the chemical formula for this.

Answer 10

the most common example of a neutralisation reaction between hydrochloric acid and sodium hydroxide.
HCI + NaOH —–> NaCI + H2O
hydrochloric acid + sodium hydroxide —> sodium chloride + water

Question 11

Explain the experiment to titrate hydrochloric acid solution against sodium hydroxide solution and then to prepare a sample of sodium chloride.

Answer 11

To make the salt, you must react exactly the right amounts of acid and base with each other.
We use an indicator to find out when the acid has been exactly neutralised.
the acid (in a burette) is slowly added to the base (in a conical flask).
The acid is added until the indicator starts to change colour.
the method of adding one solution from a burette to another solution in order to find out how much of the two solutions will just react with each other is called titration.

Question 12

What does carbon dioxide react within the air?

Answer 12

The carbon dioxide in the air reacts with rain to form a dilute solution of carbonic acid with a pH of about 5.5.

Question 13

What is the minimum pH of acid rain?

Answer 13

Rainwater with a pH of less than 5.5 is described as acid rain.

Question 14

What does acid rain contain?

Answer 14

Acid rain contains sulfuric acid and nitric acid.

Question 15

Where does sulfuric acid come from?

Answer 15

Sulfuric acid comes from sulfur dioxide in the air. Most of the sulfur dioxide in the air comes from burning fossil fuels.

Question 16

Where does nitric acid come from?

Answer 16

The nitric acid in the air comes from the emissions of car exhausts.

Question 17

What do car engines take in and what do they emit? What do these oxides of nitrogen then do?

Answer 17

Car engines take in nitrogen and oxygen from the air. Car exhausts emit oxides of nitrogen.
these oxides of nitrogen dissolve in water to form nitric acid.

Question 18

What does acid rain destroy?

Answer 18

Acid rain destroys lakes, kills fish, harms trees and attacks stone.

Question 19

How do you solve the problems of acid rain?

Answer 19

Many countries are using substances such as limestone to remove the sulfur dioxide from the emissions of power stations. Limestone is a base and this neutralises the acidic gases.
The sulfur content of fuels such as oil and gas is being reduced.
Catalytic converters are now installed in the exhaust systems of cars.
Efforts are being made to burn less fossil fuel and to use other forms of energy instead.