Page 174 - Chemistry ICSE Class X

160 ICSE Chemistry – 10

Products of electrolysis
ƒ At cathode: Copper gets deposited at the cathode.
2+
ƒ At anode: Copper ions (Cu ) are formed due to the oxidation of the
anode material (i.e., copper).
Process: When potential is applied across the solution of copper
2–
2+
sulphate, the Cu ions move towards cathode, whereas SO ions move
4
2+
towards the anode. At cathode, Cu ions get reduced to copper metal
2–
which gets deposited on the cathode. The SO ions do not get oxidised at
4
2+
the anode. Instead, copper metal of the anode gets oxidised to Cu . The
2+
Cu ions so formed go into the solution.
–
2+
At cathode: Cu (aq) + 2e o Cu(s)
from solution gets deposited at the cathode
dŚĞ ďůƵĞ ĐŽůŽƵƌ ŽĨ ĐŽƉƉĞƌ ƐƵůƉŚĂƚĞ At anode: Cu(s) o Cu (aq) + 2e –
2+
ƐŽůƵƟŽŶ ƌĞŵĂŝŶƐ ƵŶĐŚĂŶŐĞĚ ĚƵƌŝŶŐ
ŝƚƐ ĞůĞĐƚƌŽůLJƐŝƐ ƵƐŝŶŐ ĐŽƉƉĞƌ ĂŶŽĚĞ from anode goes into the solution
Ϯн
ďĞĐĂƵƐĞ ĨŽƌ ĞǀĞƌLJ Ƶ ƌĞĚƵĐĞĚ Ăƚ Thus, the net reaction due to electrolysis of copper sulphate solution
Ϯн
ĐĂƚŚŽĚĞ͕ Ă Ƶ ŝŽŶ ŝƐ ƉƌŽĚƵĐĞĚ ĚƵĞ using copper electrodes is
ƚŽ ŽdžŝĚĂƟŽŶ Ăƚ ƚŚĞ ĂŶŽĚĞ͘
Cu(s) o Cu(s)
from anode gets deposited at the cathode
This causes dissolution of copper anode and deposition of copper
metal on the cathode.
ASSIGNMENT 2
Activity series of metals and cations, Activity series of anions,
Preferential discharge of ions at the electrodes, Some examples of electrolysis

ϭ͘ Ɛ ǁĞ ĚĞƐĐĞŶĚ ƚŚĞ ĞůĞĐƚƌŽĐŚĞŵŝĐĂů ƐĞƌŝĞƐ ĐŽŶƚĂŝŶŝŶŐ ĐĂƟŽŶƐ͕ ƚŚĞ ƚĞŶĚĞŶĐLJ ŽĨ ƚŚĞ ĐĂƟŽŶ ƚŽ ŐĞƚ ____________ ;ŽdžŝĚŝƐĞĚͬ
ƌĞĚƵĐĞĚͿ Ăƚ ƚŚĞ ĐĂƚŚŽĚĞ ŝŶĐƌĞĂƐĞƐ͘
Ϯ ͘ d Ś Ğ ____________ ;ŚŝŐŚĞƌͬůŽǁĞƌͿ ŝƐ ƚŚĞ ĐŽŶĐĞŶƚƌĂƟŽŶ ŽĨ ĂŶ ŝŽŶ ŝŶ Ă ƐŽůƵƟŽŶ͕ ƚŚĞ ŐƌĞĂƚĞƌ ŝƐ ƚŚĞ ƉƌŽďĂďŝůŝƚLJ ŽĨ ŝƚƐ ďĞŝŶŐ
ĚŝƐĐŚĂƌŐĞĚ Ăƚ ŝƚƐ ĂƉƉƌŽƉƌŝĂƚĞ ĞůĞĐƚƌŽĚĞ͘
ʹ
н
ʹ
Ϯʹ
н
н
ϯ͘ ŽŶƐŝĚĞƌ ƚŚĞ ĨŽůůŽǁŝŶŐ ŝŽŶƐ ƚŽ ďĞ ƉƌĞƐĞŶƚ ŝŶ Ă ƐŽůƵƟŽŶ͕ EĂ ͕ < ͕ , ͕ ^K ͕ ů ͕ K, ͘ /Ĩ ƉůĂƟŶƵŵ ĞůĞĐƚƌŽĚĞƐ ĂƌĞ ƵƐĞĚ ŝŶ ŝƚƐ
ϰ
ĞůĞĐƚƌŽůLJƐŝƐ͕ ŶĂŵĞ
;ĂͿ dŚĞ ŝŽŶ ƚŚĂƚ ǁŽƵůĚ ďĞ ĚŝƐĐŚĂƌŐĞĚ Ăƚ ƚŚĞ ĂŶŽĚĞ͕ ;ďͿ dŚĞ ŝŽŶ ƚŚĂƚ ǁŽƵůĚ ďĞ ĚŝƐĐŚĂƌŐĞĚ Ăƚ ƚŚĞ ĐĂƚŚŽĚĞ͘
;ĐͿ 'ŝǀĞ Ă ƌĞĂƐŽŶ ƚŽ ƐƵƉƉŽƌƚ LJŽƵƌ ĂŶƐǁĞƌ ŝŶ ;ĂͿ ĂŶĚ ;ďͿ͘
ϰ͘ ƚ ǁŚŝĐŚ ĞůĞĐƚƌŽĚĞ ĂƌĞ ƚŚĞ ŵĞƚĂůůŝĐ ŝŽŶƐ ĚŝƐĐŚĂƌŐĞĚ ĚƵƌŝŶŐ ĞůĞĐƚƌŽůLJƐŝƐ͍
ϱ͘ 'ŝǀĞ ƌĞĂƐŽŶƐ ĨŽƌ ƚŚĞ ĨŽůůŽǁŝŶŐ͗ WƌŽůŽŶŐĞĚ ĞůĞĐƚƌŽůLJƐŝƐ ŽĨ ĐŽƉƉĞƌ ƐƵůƉŚĂƚĞ ƐŽůƵƟŽŶ ;ŝ͘Ğ͕͘ ƵŶƟů ƚŚĞ ďůƵĞ ĐŽůŽƵƌ ŽĨ ƚŚĞ ƐŽůƵƟŽŶ
ŝƐ ĚŝƐĐŚĂƌŐĞĚͿ ďĞƚǁĞĞŶ ƉůĂƟŶƵŵ ĞůĞĐƚƌŽĚĞƐ͕ ƌĞƐƵůƚƐ ŝŶ ƚŚĞ ĨŽƌŵĂƟŽŶ ŽĨ ŚLJĚƌŽŐĞŶ ŐĂƐ Ăƚ ƚŚĞ ĐĂƚŚŽĚĞ ĂŶĚ ŽdžLJŐĞŶ Ăƚ ƚŚĞ
ĂŶŽĚĞ͘
ϲ͘ EĂŵĞ ƚŚĞ ƉƌŽĚƵĐƚƐ ĨŽƌŵĞĚ ĚƵƌŝŶŐ ƚŚĞ ĞůĞĐƚƌŽůLJƐŝƐ ŽĨ ƚŚĞ ĨŽůůŽǁŝŶŐ͗
;ĂͿ ŝůƵƚĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ ;ďͿ DŽůƚĞŶ ůĞĂĚ ďƌŽŵŝĚĞ
;ĐͿ ƋƵĞŽƵƐ ĐŽƉƉĞƌ ƐƵůƉŚĂƚĞ ƐŽůƵƟŽŶ ƵƐŝŶŐ ĐŽƉƉĞƌ ĞůĞĐƚƌŽĚĞƐ͘
ϳ͘ ^ƚĂƚĞ ƚŚĞ ƌĞĂĐƟŽŶ ŽĐĐƵƌƌŝŶŐ Ăƚ ƚŚĞ ĂŶŽĚĞ ĚƵƌŝŶŐ ƚŚĞ ĞůĞĐƚƌŽůLJƐŝƐ ŽĨ
;ĂͿ ŽƉƉĞƌ ƐƵůƉŚĂƚĞ ƐŽůƵƟŽŶ ƵƐŝŶŐ Ă ĐŽƉƉĞƌ ĂŶŽĚĞ
;ďͿ ŽƉƉĞƌ ƐƵůƉŚĂƚĞ ƐŽůƵƟŽŶ ƵƐŝŶŐ Ă ƉůĂƟŶƵŵ ĂŶŽĚĞ
ϴ͘ ;ĂͿ tŚŝĐŚ ŽƵƚ ŽĨ Ŷ ĂŶĚ Ƶ ǁŽƵůĚ ŽĐĐƵƌ ŵŽƌĞ ƌĞĂĚŝůLJ ŝŶ ŶĂƚƵƌĞ ĂƐ ŵĞƚĂů ĂŶĚ ǁŚŝĐŚ ĂƐ Ă ĐŽŵƉŽƵŶĚ͍
;ďͿ tŚLJ ĐĂŶŶŽƚ ǁĞ ƐƚŽƌĞ ŐEK ƐŽůƵƟŽŶ ŝŶ Ă ĐŽƉƉĞƌ ĐŽŶƚĂŝŶĞƌ͍
ϯ
ϵ͘ ƵƌŝŶŐ ĞůĞĐƚƌŽůLJƐŝƐ ŽĨ ĂŶ ĂƋƵĞŽƵƐ ƐŽůƵƟŽŶ ŽĨ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ ďĞƚǁĞĞŶ ƉůĂƟŶƵŵ ĞůĞĐƚƌŽĚĞƐ͕ ƚǁŽ ƚLJƉĞƐ ŽĨ ĂŶŝŽŶƐ ŵŝŐƌĂƚĞ
ƚŽǁĂƌĚƐ ĂŶŽĚĞ ďƵƚ ŽŶůLJ ŽŶĞ ŽĨ ƚŚĞŵ ŝƐ ĚŝƐĐŚĂƌŐĞĚ͘
;ĂͿ EĂŵĞ ƚŚĞ ƚǁŽ ĂŶŝŽŶƐ͘
;ďͿ EĂŵĞ ƚŚĞ ŵĂŝŶ ƉƌŽĚƵĐƚ ŽĨ ƚŚĞ ĚŝƐĐŚĂƌŐĞ ŽĨ ĂŶŝŽŶ Ăƚ ƚŚĞ ĂŶŽĚĞ ĂŶĚ ǁƌŝƚĞ ƚŚĞ ĂŶŽĚŝĐ ƌĞĂĐƟŽŶ͘
;ĐͿ EĂŵĞ ƚŚĞ ƉƌŽĚƵĐƚ Ăƚ ƚŚĞ ĐĂƚŚŽĚĞ ĂŶĚ ǁƌŝƚĞ ƚŚĞ ƌĞĂĐƟŽŶ͘
;ĚͿ Ž LJŽƵ ŶŽƟĐĞ ĂŶLJ ĐŚĂŶŐĞ ŝŶ ĐŽůŽƵƌ͘ ^ƚĂƚĞ ǁŚLJ͍