Page 98 - Chemistry ICSE Class X

84 ICSE Chemistry – 10

ƒ ŽŶĐĞŶƚƌĂƚĞ ƚŚĞ ĮůƚƌĂƚĞ ;ŝŶ ĐŚŝŶĂ ĚŝƐŚͿ ďLJ ŚĞĂƟŶŐ ƵŶƟů ƚŚĞ ĐƌLJƐƚĂůůŝƐĂƟŽŶ ƉŽŝŶƚ͘
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ƒ ůůŽǁ ƚŚĞ ĐŽŶĐĞŶƚƌĂƚĞĚ ĮůƚƌĂƚĞ ƚŽ ĐŽŽů͘ ůƵĞ ĐƌLJƐƚĂůƐ ŽĨ ĐŽƉƉĞƌ ƐƵůƉŚĂƚĞ ƉĞŶƚĂŚLJĚƌĂƚĞ ; Ƶ^K ϱ, KͿ ĂƉƉĞĂƌ ƚŽ
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ĨŽƌŵ͘
ƒ ^ĞƉĂƌĂƚĞ ƚŚĞ ĐƌLJƐƚĂůƐ ďLJ ĚƌĂŝŶŝŶŐ ŽƵƚ ƚŚĞ ŵŽƚŚĞƌ ůŝƋƵŽƌ͘
ƒ ƌLJ ƚŚĞ ĐƌLJƐƚĂůƐ ďLJ ƉƌĞƐƐŝŶŐ ƚŚĞŵ ůŝŐŚƚůLJ ǁŝƚŚŝŶ ƚŚĞ ĨŽůĚƐ ŽĨ ĮůƚĞƌ ƉĂƉĞƌƐ͘

How are sodium sulphate crystals prepared
Sodium sulphate (Na SO ) is normal salt of the parent acid, sulphuric acid
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ŽƉƉĞƌ ƐƵůƉŚĂƚĞ ŝƐ ĂůƐŽ ĐĂůůĞĚ blue (H SO ) and parent base, sodium hydroxide (NaOH).
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Sodium sulphate when crystallised from its aqueous solution, forms
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white coloured crystals of sodium sulphate decahydrate (Na SO 10H O).
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ACTIVITY 6 Principle: ^ŽĚŝƵŵ ƐƵůƉŚĂƚĞ ĐĂŶ ďĞ ƉƌĞƉĂƌĞĚ ďLJ ƚŚĞ ĂĐƟŽŶ ŽĨ ĚŝůƵƚĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ ŽŶ ƐŽĚŝƵŵ ŚLJĚƌŽdžŝĚĞ ƐŽůƵƟŽŶ ΀EĂK,;aqͿ΁͘
Aim: To prepare sodium sulphate crystals
/Ŷ ƚŚŝƐ ƌĞĂĐƟŽŶ͕ ĂĐŝĚ ĂŶĚ ďĂƐĞ ƌĞĂĐƚ ƚŽ ĨŽƌŵ ƐĂůƚ ĂŶĚ ǁĂƚĞƌ͘ ^Ž͕ ŵĞƚŚŽĚ ƵƐĞĚ ĨŽƌ ƚŚĞ ƉƌĞƉĂƌĂƟŽŶ ŽĨ ƐŽĚŝƵŵ ƐƵůƉŚĂƚĞ
ŝƐ ŶĞƵƚƌĂůŝƐĂƟŽŶ͘
Reagents required: ^ŽĚŝƵŵ ŚLJĚƌŽdžŝĚĞ ƐŽůƵƟŽŶ͕ ĚŝůƵƚĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ͕ ƉŚĞŶŽůƉŚƚŚĂůĞŝŶ ŝŶĚŝĐĂƚŽƌ

ZĞĂĐƟŽŶ͗ Ϯ E Ă K , ; aqͿ н , SO ;aqͿ o E Ă 2 SO ;aqͿ н Ϯ, O
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ƐŽĚŝƵŵ ŚLJĚƌŽdžŝĚĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ ƐŽĚŝƵŵ ƐƵůƉŚĂƚĞ ƐŽůƵƟŽŶ
crystallization
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E Ă 2 SO ;aqͿ o E Ă 2 SO ϭϬ, K н DŽƚŚĞƌ ůŝƋƵŽƌ
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ĐƌLJƐƚĂůƐ ŽĨ ƐŽĚŝƵŵ ƐƵůƉŚĂƚĞ
Procedure: &ŽůůŽǁ ƚŚĞ ƐƚĞƉƐ ŐŝǀĞŶ ďĞůŽǁ͗
ƒ dĂŬĞ ĂďŽƵƚ ϱϬ ŵ> ŽĨ ƐŽĚŝƵŵ ŚLJĚƌŽdžŝĚĞ ƐŽůƵƟŽŶ ŝŶ Ă ďĞĂŬĞƌ͘
ƒ ĚĚ ϭͲϮ ĚƌŽƉƐ ŽĨ ƉŚĞŶŽůƉŚƚŚĂůĞŝŶ ŝŶƚŽ ƚŚĞ ƐŽůƵƟŽŶ ŽĨ ƐŽĚŝƵŵ ŚLJĚƌŽdžŝĚĞ
ƒ ^Ğƚ ƵƉ Ă ďƵƌĞƩĞ ĮůůĞĚ ǁŝƚŚ ĚŝůƵƚĞ ƐƵůƉŚƵƌŝĐ ĂĐŝĚ͘
ƒ ZƵŶ ƚŚĞ ĂĐŝĚ ĨƌŽŵ ƚŚĞ ďƵƌĞƩĞ ĚƌŽƉǁŝƐĞ ƵŶƟů ƚŚĞ ƉŝŶŬ ĐŽůŽƵƌ ŽĨ ƚŚĞ ƐŽůƵƟŽŶ ĚŝƐĂƉƉĞĂƌƐ Ăƚ ƚŚĞ ůĂƐƚ ĚƌŽƉ͘
ƒ dƌĂŶƐĨĞƌ ƚŚĞ ƌĞƐƵůƟŶŐ ƐŽůƵƟŽŶ ƚŽ ĂŶ ĞǀĂƉŽƌĂƟŶŐ ĚŝƐŚ͕ ĂŶĚ ĂůůŽǁ ǁĂƚĞƌ ƚŽ ĞǀĂƉŽƌĂƚĞ Ăƚ ƌŽŽŵ ƚĞŵƉĞƌĂƚƵƌĞ͘
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ƒ ŽůůĞĐƚ ƚŚĞ ĐƌLJƐƚĂůƐ ŽĨ ƐŽĚŝƵŵ ƐƵůƉŚĂƚĞ ĚĞĐĂŚLJĚƌĂƚĞ ;EĂ SO ϭϬ, KͿ͘
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ƒ ƌLJ ƚŚĞ ĐƌLJƐƚĂůƐ ďLJ ƉƌĞƐƐŝŶŐ ƚŚĞŵ ůŝŐŚƚůLJ ǁŝƚŚŝŶ ƚŚĞ ĨŽůĚƐ ŽĨ ĮůƚĞƌ ƉĂƉĞƌƐ͘
/Ŷ ƚŚŝƐ ĞdžƉĞƌŝŵĞŶƚ͕ ŝŶ ƉůĂĐĞ ŽĨ ƐŽĚŝƵŵ
ŚLJĚƌŽdžŝĚĞ͕ ƐŽĚŝƵŵ ĐĂƌďŽŶĂƚĞ ĐĂŶ
ĂůƐŽ ďĞ ƵƐĞĚ͘ /Ŷ ƐƵĐŚ Ă ĐĂƐĞ͕ ŵĞƚŚLJů
ŽƌĂŶŐĞ ŝƐ ƵƐĞĚ ĂƐ ƚŚĞ ŝŶĚŝĐĂƚŽƌ͘ ƚ ƚŚĞ
ĞŶĚ ƉŽŝŶƚ͕ ĐŽůŽƵƌ ĐŚĂŶŐĞ ǁŝůů ďĞ ĨƌŽŵ
LJĞůůŽǁ ƚŽ ƌĞĚ͘

Fig. 3.4 Preparation of sodium sulphate
How is sodium hydrogencarbonate prepared
Sodium hydrogencarbonate (or sodium bicarbonate, NaHCO ) is an acid
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salt of the base, sodium hydroxide (NaOH) and the acid, carbonic acid
(H CO ).
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