chem topic 3

Question 1

What ion do acids release in aqueous solution?

Answer 1

Hydrogen ions (H⁺)

Question 2

What ion do alkalis release in aqueous solution?

Answer 2

Hydroxide ions (OH⁻)

Question 3

What does a pH of 7 indicate?

Answer 3

A neutral solution

Question 4

What color is phenolphthalein in acid and alkali?

Answer 4

Colorless in acid, pink in alkali

Question 5

What color is methyl orange in acid and alkali?

Answer 5

Red in acid, yellow in alkali

Question 6

What happens to pH when H⁺ concentration increases tenfold?

Answer 6

The pH decreases by 1

Question 7

What is the difference between a dilute and a concentrated acid?

Answer 7

Concentration refers to the amount of acid in a certain volume of solution

Question 8

What is the difference between a weak and a strong acid?

Answer 8

Strong acids fully ionize; weak acids only partially ionize

Question 9

What is the general reaction between an acid and a base?

Answer 9

Acid + Base → Salt + Water

Question 10

What gas is produced when acids react with metals?

Answer 10

Hydrogen gas

Question 11

What is the test for hydrogen gas?

Answer 11

A lit splint makes a ‘squeaky pop’

Question 12

What is the test for carbon dioxide?

Answer 12

Turns limewater cloudy (milky)

Question 13

What are the products of acid + metal carbonate?

Answer 13

Salt + Water + Carbon Dioxide

Question 14

What is a neutralization reaction?

Answer 14

A reaction between an acid and a base/alkali forming a salt and water

Question 15

What is an electrolyte?

Answer 15

A liquid containing ions that conducts electricity

Question 16

What is electrolysis?

Answer 16

The decomposition of an ionic substance using electricity

Question 17

In electrolysis, where do cations move?

Answer 17

To the cathode (negative electrode)

Question 18

In electrolysis, where do anions move?

Answer 18

To the anode (positive electrode)

Question 19

What are the products of electrolysis of copper chloride solution?

Answer 19

Copper at cathode, chlorine gas at anode

Question 20

What are the products of electrolysis of sodium chloride solution?

Answer 20

Hydrogen gas at cathode, chlorine gas at anode

Question 21

What are the products of electrolysis of acidified water?

Answer 21

Hydrogen at cathode, oxygen at anode

Question 22

What are the products of electrolysis of molten lead bromide?

Answer 22

Lead at cathode, bromine at anode

Question 23

What type of reaction occurs at the cathode?

Answer 23

Reduction (gain of electrons)

Question 24

What type of reaction occurs at the anode?

Answer 24

Oxidation (loss of electrons)

Question 25

What does the acronym OIL RIG stand for?

Answer 25

Oxidation Is Loss, Reduction Is Gain (of electrons)

Question 26

What is the half-equation for hydrogen ion reduction at the cathode?

Answer 26

2H⁺ + 2e⁻ → H₂

Question 27

What determines the products at each electrode in aqueous solutions?

Answer 27

The reactivity of the ions and water in the solution

Question 28

Why is electrolysis only used for extracting very reactive metals?

Answer 28

Because they cannot be extracted by reduction with carbon