Class 9 Science - ICSE-CHEMISTRY
Study of the First Element Hydrogen
The chapter 'Study of the First Element Hydrogen' introduces students to the lightest and most abundant element in the universe. In ICSE Chemistry Class 9, this chapter is fundamental as it covers the position of hydrogen in the periodic table, its unusual dual nature resembling both alkali metals and halogens, and the general and laboratory methods for preparing hydrogen gas. Students will learn about the Bosch process, catalytic hydrogenation, physical and chemical properties of hydrogen, and its crucial role as a reducing agent. Mastering this chapter is essential for building a strong foundation in inorganic chemistry and scoring well in board exams.
Start Learning FreeKey Concepts
Position of Hydrogen in the Periodic Table
Hydrogen occupies a unique position in Group 1 (above alkali metals) and Group 17 (above halogens) due to its electronic configuration of 1s1, showing similarities with both families.
Laboratory Preparation of Hydrogen
Hydrogen is prepared in the lab by the action of dilute hydrochloric acid or dilute sulphuric acid on active metals like granulated zinc.
Industrial Preparation (Bosch Process)
Hydrogen is manufactured on a large scale by passing steam over hot coke at 1000°C to produce water gas, followed by the separation of hydrogen.
Reducing Nature of Hydrogen
Hydrogen acts as a strong reducing agent because it removes oxygen from heated metallic oxides, such as copper oxide and lead oxide, to form pure metals and water.
Catalytic Hydrogenation
Unsaturated organic compounds like alkenes react with hydrogen in the presence of catalysts like nickel or palladium to form saturated compounds like alkanes.
Important Formulas
Board Exam Info
In ICSE Chemistry Class 9, this chapter usually carries around 5 to 8 marks. Questions often include balanced chemical equations for the preparation of hydrogen, identification of gases, observations for reduction reactions, and explaining the dual position of hydrogen in the periodic table.
Frequently Asked Questions
Why is concentrated nitric acid not used in the laboratory preparation of hydrogen?
Concentrated nitric acid is a strong oxidizing agent. Instead of liberating hydrogen gas, it oxidizes hydrogen to water and gets reduced itself to nitrogen oxides.
Why is pure zinc not preferred for laboratory preparation of hydrogen?
Pure zinc reacts extremely slowly because of the absence of impurities, whereas granulated zinc contains impurities like copper which act as a catalyst to speed up the reaction.
How is hydrogen collected during its laboratory preparation?
Hydrogen is collected by the downward displacement of water because it is very sparingly soluble in water and is much lighter than air.
Learn Study of the First Element Hydrogen with Your AI Tutor
10 different ways to study this chapter. Free for 3 chapters per day.
Lecture
Key Points
Interactive
Quiz
Flashcards