Untitled Deck Flashcards
What is the common name for hydrogen chloride?
Muriatic acid
What is the molecular mass (MM) of hydrogen chloride (HCl)?
36.5
What is the vapor density (VD) of hydrogen chloride?
18.25
What are the two chemicals required for the laboratory preparation of hydrogen chloride?
- Sodium Chloride (NaCl) * Concentrated Sulphuric acid (H2SO4)
Why is sodium chloride preferred in the preparation of hydrogen chloride?
It is easily available and cheap.
What happens when sodium chloride reacts with concentrated sulphuric acid at temperatures less than 200°C?
NaCl + H2SO4 → NaHSO4 + HCl
What must be maintained during the reaction to avoid forming a hard crust?
The temperature must be maintained below 200°C.
What occurs if the temperature exceeds 200°C during the preparation of hydrogen chloride?
- Forms a hard crust of sodium sulfate * Glass apparatus may crack
How is dry hydrogen chloride gas collected?
By upward displacement of air.
What is a key characteristic of hydrogen chloride gas regarding its density compared to air?
It is denser than air.
What is the solubility of hydrogen chloride in water?
Highly soluble in water.
What happens when hydrogen chloride gas is dissolved in water?
It creates a partial vacuum in the flask, causing the blue litmus solution to flow upwards.
What color change occurs with blue litmus solution when exposed to hydrochloric acid?
Turns red.
What is the concentration of hydrochloric acid at which it forms a constant boiling mixture?
22.2% HCl at 110°C.
What is the term for a solution that boils without changing its composition?
Azeotrope.
What is the primary ionization reaction of hydrochloric acid in water?
HCl + H2O → H3O+ + Cl-
What is the observation when an active metal reacts with dilute hydrochloric acid?
A colorless gas is evolved which extinguishes a burning splinter with a pop sound.
What occurs when a carbonate reacts with hydrochloric acid?
- Salt * Water * CO2
What gas is evolved when a sulfite reacts with hydrochloric acid?
Sulfur dioxide (SO2).
What type of gas is produced when a sulfate reacts with hydrochloric acid?
- Salt * Water * Sulfur dioxide (SO2)
What is the observation when silver nitrate is added to dilute hydrochloric acid?
A curdy white precipitate of silver chloride is obtained.
Why is concentrated sulphuric acid used in the preparation of hydrochloric acid?
It is a non-volatile acid with a high boiling point that displaces volatile acids.
Why can’t nitric acid be used in the laboratory preparation of hydrochloric acid?
Nitric acid is volatile and may evaporate before hydrogen chloride is formed.
What is the result of using CaO as a drying agent in the preparation of hydrochloric acid?
It reacts with HCl, forming calcium chloride.
Explain why hydrogen chloride gas is not collected over water.
It is highly soluble in water.
What is the physical state and odor of hydrogen chloride gas?
Colorless gas with a pungent odor.
What happens to dry blue litmus paper when exposed to hydrogen chloride gas?
It is not affected.
What is produced when hydrogen chloride gas reacts with ammonia?
Dense white fumes of ammonium chloride (NH4Cl).
What is the observation when a carbonate reacts with hydrochloric acid?
A colorless, odorless gas is evolved with brisk effervescence.
What must be done to avoid back-suction of water during the preparation of hydrochloric acid?
Use an inverted funnel.
What is the reason for hydrogen chloride being a strong acid in water?
It ionizes to form hydronium ions (H3O+).
What type of reaction occurs when hydrochloric acid reacts with a base?
Neutralization reaction.
What is the effect of concentrated HCl on an oxidizing agent?
It produces chlorine gas.
What is the observation when concentrated hydrochloric acid is reacted with an oxidizing agent like MnO2?
Greenish yellow gas is evolved.
What happens when a sulphite or a bisulphite reacts with dilute hydrochloric acid?
It liberates SO2
Example reactions: Na2SO3 + 2HC1(dil) → 2NaC1 + SO2 + H2O and NaHSO3 + HC1(dil) → NaC1 + H2O + SO2
Why are silver nitrate crystals dissolved in distilled water?
To avoid the formation of a curdy white precipitate of AgCl
Tap water contains chloride salts that react with AgNO3.
What is aqua regia?
A mixture of 1 part concentrated nitric acid and 3 parts concentrated hydrochloric acid
Known as the ‘King of liquids’ because it can dissolve noble metals.
Why is aqua regia referred to as the ‘King of liquids’?
Because it can dissolve noble metals like gold
This is due to the formation of nascent chlorine which combines with noble metals to form soluble chlorides.
What is the precipitate formed when silver nitrate reacts with chloride salts?
A curdy white precipitate of AgCl
This occurs when AgNO3 is dissolved in tap water.
Fill in the blank: Aqua regia is a mixture of _______ and _______.
concentrated nitric acid, concentrated hydrochloric acid
True or False: Distilled water contains dissolved salts.
False
Distilled water is free from dissolved salts.
