Page 172 - Chemistry ICSE Class IX

160 ICSE Chemistry – 9
ƒ #U C HWGN KP URCEG XGJKENGU Hydrogen is used as a fuel in rockets and
guided missiles. This is because hydrogen has the highest calori c
value.
ƒ #U CP CNVGTPCVKXG UQWTEG QH GPGTI[ As an alternative source of energy
in industry and automobiles through the fuel-cell route.
ƒ +P GZVTCEVKXG OGVCNNWTI[ Hydrogen is used as a reducing agent to
obtain metals from their oxides.

ASSIGNMENT 1

Hydrogen - occurrence, preparation, properties and uses

ϭ͘ tŚĂƚ ŝƐ ƵŶƵƐƵĂů ĂďŽƵƚ ƚŚĞ ĞůĞĐƚƌŽŶŝĐ ĐŽŶĮŐƵƌĂƟŽŶ ŽĨ ŚLJĚƌŽŐĞŶ͍
Ϯ͘ tƌŝƚĞ ƚŚĞ ƐLJŵďŽůƐ ŽĨ ƚŚƌĞĞ ŝƐŽƚŽƉĞƐ ŽĨ ŚLJĚƌŽŐĞŶ͘
ϯ͘ tƌŝƚĞ ƚŚĞ ŶĂŵĞƐ ŽĨ ƚǁŽ ƉůĂĐĞƐ ǁŚĞƌĞ ŚLJĚƌŽŐĞŶ ŽĐĐƵƌƐ͘
ϰ͘ ,Žǁ ŝƐ ŚLJĚƌŽŐĞŶ ŐĂƐ ĐŽůůĞĐƚĞĚ ĚƵƌŝŶŐ ŝƚƐ ůĂďŽƌĂƚŽƌLJ ƉƌĞƉĂƌĂƟŽŶ͍
ϱ͘ ,Žǁ ǁŽƵůĚ LJŽƵ ĐŽŶĮƌŵ ƚŚĂƚ ƚŚĞ ŐŝǀĞŶ ŐĂƐ ŝƐ ŚLJĚƌŽŐĞŶ͍
ϲ͘ ^ƚĂƚĞ ƚŚĞ ƉƌŽƉĞƌƚLJ ŽĨ ŚLJĚƌŽŐĞŶ ƚŚĂƚ ŵĂŬĞƐ ŝƚ Ă ŐŽŽĚ ĨƵĞů͘
ϳ͘ ,Žǁ ŝƐ ǁĂƚĞƌ ŐĂƐ ƉƌĞƉĂƌĞĚ͍
ϴ͘ DĞŶƟŽŶ ƐŽŵĞ ŵĂũŽƌ ƵƐĞƐ ŽĨ ŚLJĚƌŽŐĞŶ͘
ϵ͘ tŚŝĐŚ ŵĞƚĂůƐ ĂƌĞ ĂďůĞ ƚŽ ĚŝƐƉůĂĐĞ ŚLJĚƌŽŐĞŶ ĨƌŽŵ ĂĐŝĚƐ͍
ϭϬ͘ tƌŝƚĞ Ă ĐŚĞŵŝĐĂů ĞƋƵĂƟŽŶ ƐŚŽǁŝŶŐ ƚŚĞ ƌĞĚƵĐŝŶŐ ĐŚĂƌĂĐƚĞƌ ŽĨ ŚLJĚƌŽŐĞŶ͘

Let us Answer Some More Questions

Why is hydrogen assigned a special position in the periodic table?
Give two facts each to support
(a) hydrogen resembles alkali metals
(b) hydrogen resembles halogens.
(a) How will you prepare hydrogen using magnesium?
(b) Write chemical equation of the reaction.
(a) Write the chemical equation describing the electrolysis of water.
(b) At which electrode is hydrogen gas evolved?
Mention the physical property of hydrogen that made it suitable for using in meteorological balloons.
How is ammonia obtained using hydrogen?
Give one reaction describing the reducing character of hydrogen.
Give balanced chemical equations for the preparation of hydrogen using the following substances:
(a) acidulated water (b) cold water (c) a metal hydride (d) steam
You are provided with dilute hydrochloric acid and samples of the following metals: Sodium, calcium,
magnesium, iron, zinc, lead, copper and silver.
Name:
(a) The metals that would not liberate hydrogen from the acid.
(b) The metal(s) that would react explosively with the acid.
(c) A metal that is above hydrogen in the activity series, yet does not displace hydrogen. Also give a reason for
this behaviour.
(d) A metal that liberates hydrogen very slowly from the acid.
(e) A metal that reacts moderately with the acid.
Instead of dilute hydrochloric acid, you are provided with nitric acid, would hydrogen be liberated? Explain.