Page 95 - Chemistry ICSE Class X

Study of Acids, Bases and Salts 81
ƒ Lead salts. Some insoluble salts of lead can be obtained by reacting
lead nitrate with the appropriate reagent. For example,
Pb(NO ) (aq) + HCl(aq) o PbCl (s)p + 2HNO (aq)
3
3 2
2
lead nitrate hydrochloric acid lead chloride
Pb(NO ) (aq) + Na CO (aq) o PbCO (s)p + 2NaNO (aq)
3 2
3
3
3
2
lead carbonate Ŷ K ŝƐ ĂŶ ŝŶƐŽůƵďůĞ ƐĂůƚ͘ /ƚ ĐĂŶ ĂůƐŽ
3
Pb(NO ) (aq) + H SO (aq) o PbSO (s)p + 2HNO (aq) ďĞ ƉƌĞƉĂƌĞĚ ďLJ ƚŚĞ ƌĞĂĐƟŽŶ͗
2
3
4
4
3 2
lead sulphate Ŷ^K ;aqͿ н EĂ CO ;aqͿ
3
2
4
ƒ Salts of silver. Some insoluble salts of silver can be obtained by p
reacting silver nitrate solution with the appropriate reagent. For Ŷ K ;sͿ н EĂ SO ;aqͿ
2
4
3
example,
AgNO (aq) + NaX(X = Cl, Br, I) o AgX(X = Cl, Br, I)p + NaNO (aq)
3
3
silver nitrate sodium halide silver halide
Silver chloride — White precipitate
Silver bromide — Pale yellow
Silver iodide — Yellow
ƒ Salts of barium: Some insoluble salts of barium can be obtained by
reacting solution of barium chloride with appropriate reagent.
BaCl (aq) + H SO (dil.) o BaSO (s)p + 2HCl(aq)
4
2
2
4
barium chloride barium sulphate
(white ppt.)
BaCl (aq) + Na CO (aq) o BaCO (s)p + 2NaCl(aq)
3
2
3
2
barium chloride barium carbonate dĂƉ ǁĂƚĞƌ ƐŚŽƵůĚ ŶŽƚ ďĞ ƵƐĞĚ ĨŽƌ
ƉƌĞƉĂƌŝŶŐ ƚŚĞ ƐŽůƵƟŽŶ ŽĨ ůĞĂĚ
Laboratory Preparation of Some Normal and ŶŝƚƌĂƚĞ ďĞĐĂƵƐĞ ŝƚ ŐĞŶĞƌĂůůLJ ĐŽŶƚĂŝŶƐ
2+
–
CI ǁŚŝĐŚ ƌĞĂĐƚƐ ǁŝƚŚ Wď ŝŽŶƐ ƚŽ
Acid Salts ŵĂŬĞ Wď ů ĂŶĚ ŵĂŬĞ ƚŚĞ ƐŽůƵƟŽŶ
2
ƚƵƌďŝĚ͘
In this section, the preparation of the following normal and acid salts is
described. ŝƌĞĐƚ ĂĚĚŝƟŽŶ ŽĨ ŚLJĚƌŽĐŚůŽƌŝĐ
ĂĐŝĚ ƚŽ ůĞĂĚ ĐĂƌďŽŶĂƚĞ ŝƐ ŶŽƚ
Table 3.2 Some salts and their chemical formulae ƌĞĐŽŵŵĞŶĚĞĚ ĨŽƌ ƚŚĞ ƉƌĞƉĂƌĂƟŽŶ
ŽĨ ůĞĂĚ ĐŚůŽƌŝĚĞ ďĞĐĂƵƐĞ ůĞĂĚ
Normal salts Acid salts ĐŚůŽƌŝĚĞ ďĞŝŶŐ ŝŶƐŽůƵďůĞ͕ ĨŽƌŵƐ
Lead chloride PbCl 2 Sodium hydrogencarbonate NaHCO 3 Ă ůĂLJĞƌ ŽŶ ƚŚĞ ƐƵƌĨĂĐĞ ŽĨ ůĞĂĚ
ĐĂƌďŽŶĂƚĞ ĂŶĚ ǁŝůů ŶŽƚ ĂůůŽǁ ƚŚĞ
Ferric chloride FeCl 3 Sodium hydrogensulphate NaHSO 4 ƌĞĂĐƟŽŶ ƚŽ ƉƌŽĐĞĞĚ ĨƵƌƚŚĞƌ͘
Zinc sulphate ZnSO 4 /ƚ ŝƐ ĨŽƌ ƚŚŝƐ ƌĞĂƐŽŶ ƚŚĂƚ ůĞĂĚ
Copper sulphate CuSO . 5H O ĐĂƌďŽŶĂƚĞ ŝƐ ĮƌƐƚ ĐŽŶǀĞƌƚĞĚ ƚŽ ůĞĂĚ
2
4
ŶŝƚƌĂƚĞ͕ ǁŚŝĐŚ ŝƐ ƐŽůƵďůĞ ŝŶ ǁĂƚĞƌ͘
.
Sodium sulphate Na SO 10H O
4
2
2
How is lead chloride prepared ŚůŽƌŝŶĞ ŐĂƐ ŝƐ ŚŝŐŚůLJ ƉŽŝƐŽŶŽƵƐ͘ /ƚ
ƐŚŽƵůĚ ďĞ ŚĂŶĚůĞĚ ǀĞƌLJ ĐĂƌĞĨƵůůLJ͘
Lead chloride is a normal salt of the base Pb(OH) and acid HCl.
2
ACTIVITY 2 Aim: To prepare lead chloride
Principle: >ĞĂĚ ĐŚůŽƌŝĚĞ ĐĂŶ ďĞ ƉƌĞƉĂƌĞĚ ďLJ ƉƌĞĐŝƉŝƚĂƟŽŶ ;Žƌ ĚŽƵďůĞ ĚĞĐŽŵƉŽƐŝƟŽŶͿ ŵĞƚŚŽĚ͘
Reagents required: &ŽůůŽǁŝŶŐ ƌĞĂŐĞŶƚƐ ĂƌĞ ƌĞƋƵŝƌĞĚ ĨŽƌ ƚŚŝƐ ƉƌĞƉĂƌĂƟŽŶ͗
ƒ ^ŽůƵƟŽŶ ŽĨ ůĞĂĚ ĂĐĞƚĂƚĞ Žƌ ůĞĂĚ ŶŝƚƌĂƚĞ

ƒ ŝůƵƚĞ ŚLJĚƌŽĐŚůŽƌŝĐ ĂĐŝĚ
ZĞĂĐƟŽŶ͗
Wď;EK Ϳ ;aqͿ н Ϯ, ů;aqͿ o W ď ů ;sͿp н Ϯ,EK ;aqͿ
3 2 2 3
ůĞĂĚ ŶŝƚƌĂƚĞ ŚLJĚƌŽĐŚůŽƌŝĐ ĂĐŝĚ ůĞĂĚ ĐŚůŽƌŝĚĞ ;Ă normal saltͿ