What is Lead Acetate?
Lead acetate is an ionic compound with the formula [Pb(CH3COO)2], in which lead is present in +2 oxidation state. It is a white crystalline solid. It has a slight sweet taste. It is also known as Plumbous acetate, salt of Saturn, sugar of lead, Goulard’s powder or lead diacetate. Its systematic IUPAC name is Lead(II) ethanoate. Lead acetate is also toxic like other lead compounds. But it still has various applications such as a fixative and also as a reagent for synthesis of other compounds. It was also used as a sweetener but soon it was banned due to its toxic nature. It was discovered in the US in 1944.
Lead(II) acetate has Pb+2 cation and CH3COO- anion. It is a water - soluble compound. It is commonly found as trihydrate lead acetate which is particularly known as sugar of lead due to its sweet taste. Molecular formula of trihydrate lead acetate is Pb(CH3COO)2.3H2O. It is white in color and a monoclinic crystalline substance which is soluble in water. It is used in dyeing, gold cyanidation plants, paints etc.
Structure of Lead Acetate
It is an ionic compound which is formed by the reaction of elemental lead and acetic acid. It has one Pb2+ ion and two CH3COO- ions. As lead cation contains +2 charge while each acetate anion has -1 charge, so the compound lead(II) acetate contains zero charge.
[Image will be Uploaded Soon]
Properties of Lead Acetate
Physical and chemical properties of lead acetate - Properties of lead acetate are listed below –
Molar mass of anhydrous lead acetate is 325.29 g.mol-1.
Molar mass of its trihydrate (Pb(CH3COO)2.3H2O) form is 379.33 g.mol-1.
It is a white colored efflorescent crystalline solid.
It is slightly sweet in taste.
It has a pleasant acetic smell.
Its density in its anhydrous form is 3.25 g.cm-3 while in its trihydrate form is 2.55 g.cm-3.
Melting point of anhydrous lead acetate is 280 °C. While melting point of trihydrate lead acetate is 75 °C.
Anhydrous lead acetate is soluble in water and its solubility increases as temperature increases. For example, 19.8 gram of it is soluble in 100ml water at 0 °C while 44.3 grams are soluble in 100ml water at 20 °C.
It is also soluble in alcohol, glycerol etc.
It is highly soluble in methanol. For example, at 66.1 °C temperature, 102.75 grams of lead acetate is soluble in 100 grams of methanol.
Its 20 grams are soluble in 100 g of glycerol at 15 °C.
It has monoclinic crystal structure.
It is a non – flammable but toxic compound. On oral consumption, 400mg/kg of it can be lethal for mice.
It is basic in nature.
Its standard enthalpy of formation is -960.9 kJ.mol-1.
Reaction with hydrogen sulfide – It reacts with hydrogen sulfide and forms lead sulfide and acetic acid. Reaction is given below –
Pb(C2H3O2)2 + H2S → PbS + 2CH3COOH
Reaction with potassium chromate – It reacts with potassium chromate and forms lead chromate and potassium acetate. Reaction is given below –
K2CrO4 + Pb(C2H3O2)2 → PbCrO4 + 2CH3COOK
Production of Lead Acetate
It can be produced by following two methods –
By reaction of acetic acid, hydrogen peroxide and elemental lead
By reaction of copper acetate and lead metal
By reaction of acetic acid, hydrogen peroxide and elemental lead – Elemental lead is boiled in acetic acid and hydrogen peroxide which result into lead acetate and water. Lead carbonate or lead oxide can be used in place of elemental lead. Reaction is given below –
Pb(s) + H2O2(aq) + 2H+(aq) → Pb2+(aq) + 2H2O(l)
Pb2+(aq) + 2CH3COO−(aq) → Pb(CH3COO)2(aq)
By reaction of copper acetate and lead metal – Lead metal on reaction with copper acetate displaces copper metal and forms lead acetate by single displacement reaction. The equation is given below –
Cu(CH3COO)2 + Pb → Cu + Pb(CH3COO)2
Uses of Lead Acetate
Lead acetate was used as a sweetener due to its slight sweet taste. Ancient Romans used to boil grape juice in lead pots to produce reduced sugar syrup. This sugar syrup was called defrutum. But after a few years it was recognized that lead compounds (or lead acetate) are toxic and were causing lead poisoning in those who were consuming the sugar syrup. Currently, its usage as a sweetener is banned.
Lead acetate has been widely used in the cosmetic industry for a long time but due to its toxicity, presently its use has been limited. Nowadays it is mainly used in production of hair coloring products. Although in many places such as Canada, European Union and California lead acetate is completely banned in food items and cosmetic products as well due its carcinogenicity and reproductive toxicity. It was also used as a remedy for sore nipples.
Lead acetate solution which is also known as Goulard’s Extract is used as an astringent to constrict mucous membrane and exposed tissues in modern medicine. Specifically, Goulard’s extract is a solution of lead acetate and lead oxide which was first introduced by French surgeon Thomas Goulard.
A paper made up of lead acetate is used in detection of poisonous gas H2S. Moist lead acetate on reaction with hydrogen sulfide gas gives lead sulfide.
It is also used in cleaning and maintenance of stainless steel suppressors and compensators. It was also used in making matchsticks during the Medieval period. Sugar of lead is used in boiled linseed oil to increase its effectiveness.
This ends our coverage on the topic “lead acetate”. We hope you enjoyed learning and were able to grasp the concepts. We hope after reading this article you will be able to solve problems based on the topic. If you are looking for solutions of NCERT Textbook problems based on this topic, then log on to Vedantu website or download Vedantu Learning App. By doing so, you will be able to access free PDFs of NCERT Solutions as well as Revision notes, Mock Tests and much more.