Page 167 - Chemistry ICSE Class X

Electrolysis 153
–
X o ½ X 2 + e – (Oxidation)
anion electron
oxidation
Š In case anions are not oxidised under the conditions, either of the
following occurs:
y If the anode is of attackable material, it gets oxidised and the
corresponding ion (cation) goes into the solution.
Or
–
y The anion furnished by the solvent (generally water), i.e., OH
gets oxidised to form oxygen and water.
ƒ The products formed at the electrodes, due to electrolysis, either get
deposited at the electrode or come out of the electrode in the form of
a gaseous product.

ASSIGNMENT 1

Electrolytes, Conduction of electricity through electrolytes, Electrolysis

ϭ͘ tŚŝĐŚ ŽĨ ƚŚĞ ĨŽůůŽǁŝŶŐ ĐŽŶĚƵĐƚƐ ĞůĞĐƚƌŝĐŝƚLJ͍പപ;ĂͿ ĂƋƵĞŽƵƐ ƐŽůƵƟŽŶ ŽĨ ƐŽĚŝƵŵ ĐŚůŽƌŝĚĞപപ;ďͿ ĐĂƌďŽŶ ƚĞƚƌĂĐŚůŽƌŝĚĞ͘
Ϯ͘ tŚĂƚ ŝƐ ƚŚĞ ĚŝīĞƌĞŶĐĞ ďĞƚǁĞĞŶ ĂŶ ĞůĞĐƚƌŽůLJƚĞ ĂŶĚ Ă ŶŽŶĞůĞĐƚƌŽůLJƚĞ͍
ϯ͘ ŽŵƉůĞƚĞ ƚŚĞ ĨŽůůŽǁŝŶŐ ƐƚĂƚĞŵĞŶƚ͗ ƵƌŝŶŐ ĞůĞĐƚƌŽůLJƐŝƐ ŽĨ Ă ƐĂůƚ ƐŽůƵƟŽŶ͕ ƚŚĞ ĐĂƟŽŶƐ ĂƌĞ ĂƩƌĂĐƚĞĚ ƚŽǁĂƌĚƐ _________ ͘
ϰ͘ tƌŝƚĞ ƚŚĞ ƌĞĂĐƟŽŶƐ ǁŚŝĐŚ ŽĐĐƵƌ ĚƵƌŝŶŐ ƚŚĞ ĞůĞĐƚƌŽůLJƐŝƐ ŽĨ ĂĐŝĚƵůĂƚĞĚ ǁĂƚĞƌ͘
ϱ͘ tŚĂƚ ƚLJƉĞ ŽĨ ƌĞĂĐƟŽŶƐ ŽĐĐƵƌ Ăƚ ƚŚĞ ;ĂͿ ĂŶŽĚĞ ĂŶĚ ;ďͿ ĐĂƚŚŽĚĞ͍
ϲ͘ ŝīĞƌĞŶƟĂƚĞ ďĞƚǁĞĞŶ ĂŶ ĞůĞĐƚƌŽůLJƚĞ ĂŶĚ Ă ŵĞƚĂůůŝĐ ĐŽŶĚƵĐƚŽƌ͘
ϳ͘ ĂŶ ĞůĞĐƚƌŽůLJƐŝƐ ďĞ ĐŽŶƐŝĚĞƌĞĚ ĂƐ ĂŶ ĞdžĂŵƉůĞ ŽĨ ƌĞĚŽdž ƌĞĂĐƟŽŶ͍
ϴ͘ tŚŝĐŚ ŽĨ ƚŚĞ ĨŽůůŽǁŝŶŐ ǁŽƵůĚ ĐŽŶĚƵĐƚ ĞůĞĐƚƌŝĐŝƚLJ͍
;ĂͿ dĂƉ ǁĂƚĞƌ ;ďͿ ƌLJ ĐŽŵŵŽŶ ƐĂůƚ ;ĐͿ >ŝƋƵŝĚ ŽdžLJŐĞŶ ;ĚͿ ƋƵĞŽƵƐ ƐƵŐĂƌ ƐŽůƵƟŽŶ
;ĞͿ ϭϬϬй ƉƵƌĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ
ϵ͘ ƌĂǁ Ă ůĂďĞůůĞĚ ĚŝĂŐƌĂŵ ŽĨ ƚŚĞ ƐĞƚͲƵƉ ƵƐĞĚ ŝŶ ĞůĞĐƚƌŽůLJƐŝƐ͘
ϭϬ͘ ,Žǁ ŝƐ ƚŚĞ ƉĂƐƐĂŐĞ ŽĨ ĞůĞĐƚƌŝĐŝƚLJ ƚŚƌŽƵŐŚ ĂŶ ĞůĞĐƚƌŽůLJƚĞ ĚŝīĞƌ ĨƌŽŵ ƚŚĞ ƉĂƐƐĂŐĞ ŽĨ ĞůĞĐƚƌŝĐŝƚLJ ƚŚƌŽƵŐŚ Ă ĐŽƉƉĞƌ ǁŝƌĞ͍

Activity Series: The Relative Reactivities of Metals
and Their Cations

What is the activity or electrochemical series of metals and
their cations
Some metals are more reactive than others. The tendency of a metal to lose
electrons is a measure of its reactivity. Thus, a more electropositive metal
is more reactive.
The arrangement of metals in a vertical column in the order of
decreasing reactivity is called activity series of metals or electrochemical dŚĞ ĂĐƟǀŝƚLJ ƐĞƌŝĞƐ ŽĨ ŵĞƚĂůƐ ĂŶĚ ƚŚĞŝƌ
series of metals. ŝŽŶƐ ŝƐ ĂůƐŽ ĐĂůůĞĚ ƌĞĂĐƟǀŝƚLJ ƐĞƌŝĞƐ Žƌ
ĞůĞĐƚƌŽĐŚĞŵŝĐĂů ƐĞƌŝĞƐ͘
In the activity series, the most reactive metal (the metal which can lose
electrons most easily) is placed at the top, whereas the least reactive metal
is placed at the bottom.
The more reactive metals have greater tendency to lose electrons. So,
more reactive metals are more electropositive or more metallic in nature.
Therefore, the electropositive (or metallic) character of metals decreases
as we go down from top to the bottom in the activity series of metals.
The activity series of some common metals is given in Table 6.3.