Lead (Pb) is a soft and silvery metal with atomic number 82. HCl is a strong acid with a pungent smell. Let us understand the reactions between Pb and HCl through this article.
Lead is a malleable and ductile element with high density. However, lead is less reactive than other metals but must be kept away from children. HCl is an important chemical with great industrial and laboratory importance. It has corrosive properties in the presence of moisture.
As we proceed through the article, we will learn about reactions between HCl and Pb, the type of reactions, enthalpy change, intermolecular forces and titrations.
What is the product of HCl and Pb
Hydrogen chloride (HCl) reacts with Lead (Pb) to produce lead chloride (II) (PbCl2) and hydrogen gas (H2) is released. We can write the chemical equation for the given reaction as follows:
Pb (s) + HCl (aq.) = PbCl2 (aq.) + H2 (g).
What type of reaction is HCl + Pb
Pb and HCl reaction is a single displacement reaction or substitution reaction. Lead (II) ion displaces hydrogen from hydrochloric acid to form lead (II) chloride.
How to balance HCl + Pb
Following are the steps involved in balancing the chemical equation:
- To write the general chemical equation:
- Pb + HCl = PbCl2 + H2.
- Equated the number of atoms present on the reactant side with the number of atoms on the product side.
- Here we can see that number of hydrogens needs to be balanced. Therefore, we add a coefficient of 2 with HCl. So, the new chemical equation will be:
- Pb + 2HCl = PbCl2 + H2.
- Now the number of atoms is balanced on both sides of the chemical equation. We got our balanced equation for the reaction between HCl and Pb as follows:
- Pb + 2HCl = PbCl2 + H2.
HCl + Pb titration
Pb cannot be titrated against HCl as no suitable chemical indicator is available.
HCl + Pb net ionic equation
- The net ionic equation for the reaction of Lead with HCl is:
- Pb (s) + H+ (aq.) + Cl– (aq.) = PbCl2 (s) + H2 (g).
- After balancing the ions present in the reaction, the net chemical equation changes to;
- Pb (s) + 2H+ (aq.) + 2Cl– (aq.) = PbCl2 (s) + H2 (g).
- Chloride ions and protons were the only ions formed during the reaction.
HCl + Pb conjugate pairs
The pair of HCl and Pb itself does not have any conjugate pair.
- As HCl is a strong acid, it’s conjugates base Cl– is present in the reaction.
HCl and Pb intermolecular forces
Weak London-dispersion forces are present in the dihydrogen molecule and HCl contains dipole-dipole and London dispersion forces. As PbCl2 is ionic, ionic bonds are present between lead chloride (II) molecules.
|H2||Weak London-dispersion forces|
|HCl||1. Dipole-dipole interaction|
2. London Dispersion forces
HCl + Pb reaction enthalpy
Pb + HCl reaction enthalpy is -24.88 kJ/mol. Enthalpy of formation for the reactants and products involved in the reaction are as follows-
- Enthalpy of formation on reactant side (Pb): 0 kJ/mol
- Enthalpy of formation on reactant side (HCl): -167.16 kJ/mol
- Enthalpy of formation on the product side (PbCl2): -359.2 kJ/mol
- Enthalpy of formation on the product side (H2): 0 kJ/mol
ΔfH (Enthalpy of reaction) = Sum of standard enthalpy of formation of products – sum of standard enthalpy of formation of reactants.
ΔfH = -359.2 kJ/mol – 2(-167.16 kJ/mol)
ΔfH = -24.88 kJ/mol.
Is HCl + Pb a buffer solution
Pb + HCl is not a buffer solution as HCl being a strong acid completely dissociates into ions. Whereas to obtain a buffer solution, there should be a weak acid with its conjugate base or a weak base with its conjugate acid.
Is HCl + Pb a complete reaction
Pb + HCl is complete reaction and no further step is left. Lead (Pb) reacts with hydrogen chloride (HCl) to form lead chloride (II) (PbCl2) and hydrogen gas is released.
Pb (s) + 2HCl (aq.) = PbCl2 (aq.) + H2 (g).
Is HCl + Pb an exothermic or endothermic reaction
HCl + Pb is an exothermic reaction because reaction enthalpy for the given chemical equation has a negative value and it will release heat during the reaction. With decreasing temperature, the product yield can be increased in the reaction.
Is HCl + Pb a redox reaction
Pb with HCl reaction is a redox reaction. Lead is getting oxidized and hydrogen is getting reduced.
Is HCl + Pb a precipitation reaction
HCl + Pb is a precipitation reaction as yellow precipitates of lead chloride (II) are formed when HCl reacts with lead (II) ions.
Is HCl + Pb reversible or irreversible reaction
HCl + Pb reaction is irreversible reaction because hydrogen gas molecules are released as the chemical reaction proceeds, which cannot be added back to the reaction to revert the reactants.
Is HCl + Pb displacement reaction
HCl + Pb is a single displacement reaction or substitution reaction.
At the end, we can conclude that lead reaction with hydrochloric acid yields a yellow-coloured insoluble compound, lead chloride (II). Lead and HCl titration are not possible due to the non-availability of a suitable indicator. Hydrochloric acid and lead should both be handled with care.