Untitled Deck

Question 1

What is the common name for hydrogen chloride?

Answer 1

Muriatic acid

Question 2

What is the molecular mass (MM) of hydrogen chloride (HCl)?

Answer 2

36.5

Question 3

What is the vapor density (VD) of hydrogen chloride?

Answer 3

18.25

Question 4

What are the two chemicals required for the laboratory preparation of hydrogen chloride?

Answer 4

• Sodium Chloride (NaCl) * Concentrated Sulphuric acid (H2SO4)

Question 5

Why is sodium chloride preferred in the preparation of hydrogen chloride?

Answer 5

It is easily available and cheap.

Question 6

What happens when sodium chloride reacts with concentrated sulphuric acid at temperatures less than 200°C?

Answer 6

NaCl + H2SO4 → NaHSO4 + HCl

Question 7

What must be maintained during the reaction to avoid forming a hard crust?

Answer 7

The temperature must be maintained below 200°C.

Question 8

What occurs if the temperature exceeds 200°C during the preparation of hydrogen chloride?

Answer 8

• Forms a hard crust of sodium sulfate * Glass apparatus may crack

Question 9

How is dry hydrogen chloride gas collected?

Answer 9

By upward displacement of air.

Question 10

What is a key characteristic of hydrogen chloride gas regarding its density compared to air?

Answer 10

It is denser than air.

Question 11

What is the solubility of hydrogen chloride in water?

Answer 11

Highly soluble in water.

Question 12

What happens when hydrogen chloride gas is dissolved in water?

Answer 12

It creates a partial vacuum in the flask, causing the blue litmus solution to flow upwards.

Question 13

What color change occurs with blue litmus solution when exposed to hydrochloric acid?

Answer 13

Turns red.

Question 14

What is the concentration of hydrochloric acid at which it forms a constant boiling mixture?

Answer 14

22.2% HCl at 110°C.

Question 15

What is the term for a solution that boils without changing its composition?

Answer 15

Azeotrope.

Question 16

What is the primary ionization reaction of hydrochloric acid in water?

Answer 16

HCl + H2O → H3O+ + Cl-

Question 17

What is the observation when an active metal reacts with dilute hydrochloric acid?

Answer 17

A colorless gas is evolved which extinguishes a burning splinter with a pop sound.

Question 18

What occurs when a carbonate reacts with hydrochloric acid?

Answer 18

• Salt * Water * CO2

Question 19

What gas is evolved when a sulfite reacts with hydrochloric acid?

Answer 19

Sulfur dioxide (SO2).

Question 20

What type of gas is produced when a sulfate reacts with hydrochloric acid?

Answer 20

• Salt * Water * Sulfur dioxide (SO2)

Question 21

What is the observation when silver nitrate is added to dilute hydrochloric acid?

Answer 21

A curdy white precipitate of silver chloride is obtained.

Question 22

Why is concentrated sulphuric acid used in the preparation of hydrochloric acid?

Answer 22

It is a non-volatile acid with a high boiling point that displaces volatile acids.

Question 23

Why can’t nitric acid be used in the laboratory preparation of hydrochloric acid?

Answer 23

Nitric acid is volatile and may evaporate before hydrogen chloride is formed.

Question 24

What is the result of using CaO as a drying agent in the preparation of hydrochloric acid?

Answer 24

It reacts with HCl, forming calcium chloride.

Question 25

Explain why hydrogen chloride gas is not collected over water.

Answer 25

It is highly soluble in water.

Question 26

What is the physical state and odor of hydrogen chloride gas?

Answer 26

Colorless gas with a pungent odor.

Question 27

What happens to dry blue litmus paper when exposed to hydrogen chloride gas?

Answer 27

It is not affected.

Question 28

What is produced when hydrogen chloride gas reacts with ammonia?

Answer 28

Dense white fumes of ammonium chloride (NH4Cl).

Question 29

What is the observation when a carbonate reacts with hydrochloric acid?

Answer 29

A colorless, odorless gas is evolved with brisk effervescence.

Question 30

What must be done to avoid back-suction of water during the preparation of hydrochloric acid?

Answer 30

Use an inverted funnel.

Question 31

What is the reason for hydrogen chloride being a strong acid in water?

Answer 31

It ionizes to form hydronium ions (H3O+).

Question 32

What type of reaction occurs when hydrochloric acid reacts with a base?

Answer 32

Neutralization reaction.

Question 33

What is the effect of concentrated HCl on an oxidizing agent?

Answer 33

It produces chlorine gas.

Question 34

What is the observation when concentrated hydrochloric acid is reacted with an oxidizing agent like MnO2?

Answer 34

Greenish yellow gas is evolved.

Question 35

What happens when a sulphite or a bisulphite reacts with dilute hydrochloric acid?

Answer 35

It liberates SO2 ## Footnote Example reactions: Na2SO3 + 2HC1(dil) → 2NaC1 + SO2 + H2O and NaHSO3 + HC1(dil) → NaC1 + H2O + SO2

Question 36

Why are silver nitrate crystals dissolved in distilled water?

Answer 36

To avoid the formation of a curdy white precipitate of AgCl ## Footnote Tap water contains chloride salts that react with AgNO3.

Question 37

What is aqua regia?

Answer 37

A mixture of 1 part concentrated nitric acid and 3 parts concentrated hydrochloric acid ## Footnote Known as the 'King of liquids' because it can dissolve noble metals.

Question 38

Why is aqua regia referred to as the 'King of liquids'?

Answer 38

Because it can dissolve noble metals like gold ## Footnote This is due to the formation of nascent chlorine which combines with noble metals to form soluble chlorides.

Question 39

What is the precipitate formed when silver nitrate reacts with chloride salts?

Answer 39

A curdy white precipitate of AgCl ## Footnote This occurs when AgNO3 is dissolved in tap water.

Question 40

Fill in the blank: Aqua regia is a mixture of _______ and _______.

Answer 40

concentrated nitric acid, concentrated hydrochloric acid

Question 41

True or False: Distilled water contains dissolved salts.

Answer 41

False ## Footnote Distilled water is free from dissolved salts.