Chemistry Multiple Choice Questions on “P-Block Elements – Hydrogen Chloride”.
1. Hydrogen chloride is manufactured by the ‘salt cake’ method.
a) True
b) False
Answer: a
Clarification: Hydrogen chloride is manufactured by the ‘salt cake’ method. In this method, concentrated sulphuric acid is added to rock salt in order to form sodium sulphate and hydrogen chloride.
2. Which of the following scientists first prepared hydrogen chloride by heating common salt with sulphuric acid?
a) Rudolf Glauber
b) Joseph Priestley
c) Humphry Davy
d) Antoine Lavoisier
Answer: a
Clarification: Rudolf Glauber prepared hydrogen chloride in 1648 by heating common salt with concentrated sulphuric acid. Humphry Davy, in 1810, established its true nature and showed that it is a compound of hydrogen and chlorine.
3. How many stages is the ‘salt cake’ method performed in?
a) 1
b) 3
c) 2
d) 4
Answer: c
Clarification: The ‘salt cake’ method is an endothermic reaction. It is performed in two stages. The first stage involves the reaction between rock salt and sulphuric acid at 420K and in the second stage, the product of the first stage is heated to a temperature of 823K so that it further reacts with sulphuric acid.
4. Hydrogen chloride can be obtained from the heavy organic chemical industry.
a) True
b) False
Answer: a
Clarification: Large amount of impure HCl are obtained in recent years as a by-product from the heavy organic chemical industry. For example, HCl is produced in the conversion of 1,2-dichloroethane to vinyl chloride.
5. Which of the following is formed in the first stage of the ‘salt cake’ method?
a) Sodium sulphate
b) Sodium bisulphate
c) Sodium Chloride
d) Hydrogen
Answer: b
Clarification: In the first stage of the ‘salt cake’ method, solid sodium chloride reacts with concentrated sulphuric acid at 420K and gets coated with insoluble sodium bisulphate. This prevents further reaction and hence, the name ‘salt cake’ was given to this method.
6. Which of the following can be used to dry HCl gas?
a) Sodium hydroxide
b) Potassium hydroxide
c) Ammonium hydroxide
d) Concentrated sulphuric acid
View Answer
Answer: d
Clarification: The hydroxides are basic in nature and hence, they will react with hydrogen chloride gas. Therefore, concentrated sulphuric acid is used as a drying agent for hydrogen chloride gas since it does not react with it.
7. What is the boiling point of hydrogen chloride?
a) 168 K
b) 189 K
c) 198 K
d) 150 K
Answer: b
Clarification: Hydrogen chloride is a colourless and pungent smelling gas. It can be easily liquefied to form a colourless liquid. The boiling point of hydrogen chloride is 189 K and its freezing point is 150 K.
8. Which of the following does not react with hydrochloric acid to give chlorine as a product?
a) KMnO4
b) MnO2
c) K2Cr2O7
d) Mg
Answer: d
Clarification: Concentrated hydrochloric acid reacts with strong oxidising agents to yield chlorine gas. KMnO4, MnO2, K2Cr2O7, PbO2 are examples of oxidising agents which release chlorine on reaction with hydrochloric acid.
9. Which of the following reacts with hydrochloric acid to give hydrogen as a product?
a) Zinc
b) Sodium carbonate
c) Sodium sulphate
d) Sodium nitrate
Answer: a
Clarification: Active metals such as zinc, magnesium, iron and aluminium react with hydrochloric acid to produce their corresponding metal chlorides with the liberation of hydrogen gas. Hydrochloric acid decomposes salts of weaker acids like carbonates, sulphides and so on.
10. Which of the following is hydrochloric acid not used for?
a) Manufacture of metal chlorides
b) Preparing TNT
c) Preparation of aqua regia
d) Extracting glue from bones
Answer: b
Clarification: Hydrochloric acid reacts with metals to form their respective chlorides and so, is used in the manufacture of metal chlorides. Aqua regia is made using hydrochloric acid and nitric acid. Hydrochloric acid is also used for extracting glue from bones.