Page 162 - Chemistry ICSE Class IX

150 ICSE Chemistry – 9
2Na(s) + 2H O(l) o 2NaOH(aq) + H (g)
2
2
sodium water (cold) sodium hydroxide hydrogen
2K(s) + 2H O(l) o 2KOH(aq) + H (g)
2
2
potassium water (cold) potassium hydroxide hydrogen
Ca(s) + 2H O(l) o Ca(OH) (aq) + H (g)
2
2
2
calcium water (cold) calcium hydroxide hydrogen
Action of metals on boiling water
Metals like magnesium and aluminium in powder form decompose boiling
water, giving hydrogen gas.
Mg(s) + H O(l) o MgO(s) + H (g)
2
2
magnesium (boiling) magnesium oxide hydrogen
2Al(s) + 3H O(l) o Al O (s) + 3H (g)
3
2
2
2
aluminium (boiling) aluminium oxide hydrogen
By passing steam over heated metals
When steam is passed over some heated metals, such as zinc, magnesium
and iron, hydrogen gas is obtained.
Hydrogen so evolved is collected over water.

3Fe(s) + 4H O U Fe O (s) + 4H (g)
3
2
2
4
red hot iron (steam) ferrosoferric oxide hydrogen
Action of steam on Al and Zn
Aluminium and zinc both decompose boiling water (steam) to give
hydrogen gas.
2Al(s) + 3H O o Al O + 3H (g)
2
3
2
2
aluminium (steam) hydrogen
Zn(s) + H O o ZnO(s) + H (g)
2
2
zinc (steam)
C(s) + H O o CO(g) + H (g)
2
2
red hot coke (steam) water gas
Action of Sodium and Calcium on water
Aim: dŽ ĚĞŵŽŶƐƚƌĂƚĞ ƌĞĂĐƟŽŶ ŽĨ ƐŽĚŝƵŵ ǁŝƚŚ ǁĂƚĞƌ͘ ZĞƉŽƌƚ LJŽƵƌ ŽďƐĞƌǀĂƟŽŶƐ ĂŶĚ ǁƌŝƚĞ ĞƋƵĂƟŽŶ ĨŽƌ ƚŚĞ ƌĞĂĐƟŽŶ͘
ACTIVITY 1 Procedure:

ƒ dĂŬĞ ĨĞǁ ƉŝĞĐĞƐ ŽĨ ƐŽĚŝƵŵ ŵĞƚĂů ŝŶ ƚŚĞ ĐŽŶŝĐĂů ŇĂƐŬ ĂŶĚ

ĂƌƌĂŶŐĞ ƚŚĞ ĂƉƉĂƌĂƚƵƐ͕ ĂƐ ƐŚŽǁŶ ŝŶ ƚŚĞ ĂĚũŽŝŶŝŶŐ ĮŐƵƌĞ͘

ƒ WĂƐƐ ƚŚĞ ŐĂƐ ĞǀŽůǀĞĚ ƚŚƌŽƵŐŚ ƐŽĂƉ ƐŽůƵƟŽŶ͘ ƵďďůĞƐ ĂƌĞ
ƒ ƌŽƉ ĚŝůƵƚĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ ĨƌŽŵ Ă ĚƌŽƉƉŝŶŐ ĨƵŶŶĞů͘
ĨŽƌŵĞĚ͘
ƒ ƌŝŶŐ Ă ďƵƌŶŝŶŐ ŵĂƚĐŚƐƟĐŬ ŶĞĂƌ ƚŚĞ ŐĂƐͲĮůůĞĚ ďƵďďůĞƐ͘
ObservaƟon: tŚĞŶ ƚŚĞ ďƵƌŶŝŶŐ ŵĂƚĐŚƐƟĐŬ ŝƐ ďƌŽƵŐŚƚ ŶĞĂƌ ƚŚĞ
ŐĂƐͲĮůůĞĚ ďƵďďůĞƐ͕ ƚŚĞ ŐĂƐ ďƵƌŶƐ ǁŝƚŚ Ă ƉŽƉ ƐŽƵŶĚ͘
Conclusion: Ɛ ƚŚĞ ŐĂƐ ďƵƌŶƐ ǁŝƚŚ Ă ƉŽƉ ƐŽƵŶĚ͕ ŝƚ ŝƐ ŚLJĚƌŽŐĞŶ ŐĂƐ͘
ZĞĚƵĐƟŽŶ
Room
;ŝͿ ϮEĂ;sͿ н Ϯ, K;lͿ o Ϯ E Ă н K, ʹ н , Ϯ ;gͿ
Ϯ
ƚĞŵƉ͘
^ŽĚŝƵŵ
KdžŝĚĂƟŽŶ
^ŽĚŝƵŵ ŚLJĚƌŽdžŝĚĞ