The name of the compound PbCl4 is:
Lead tetrachloride
Lead(II) chloride
Lead(IV) chloride
Lead chloride
The correct answer and explanation is :
The correct name of the compound PbCl4 is Lead(IV) chloride.
Explanation:
The name of a chemical compound is based on the oxidation state (charge) of the metal element present and the number of atoms of each element in the compound.
In the case of PbCl4:
- Pb represents lead, a transition metal with multiple possible oxidation states. Lead can commonly exist in two oxidation states: +2 (in PbCl2) and +4 (in PbCl4).
- Cl represents chlorine, which always has a charge of -1 in ionic compounds.
To determine the oxidation state of lead in PbCl4, we use the fact that the total charge in a neutral compound must sum to zero. Chlorine has a charge of -1, and there are four chloride ions (Cl⁻) in PbCl4. Therefore, the total negative charge contributed by chlorine ions is:
[
4 \times (-1) = -4
]
For the compound to be neutral, the charge on the lead ion must balance this, meaning the lead ion must have a charge of +4:
[
\text{Charge of Pb} = +4
]
Thus, the lead ion in PbCl4 has an oxidation state of +4, which is denoted in the name as Lead(IV).
Why not the other options?
- Lead tetrachloride is a descriptive name that directly indicates four chlorine atoms, but it does not specify the oxidation state of lead. Hence, it is less precise than Lead(IV) chloride.
- Lead(II) chloride refers to the compound PbCl2, where lead has an oxidation state of +2, which is not the case here.
- Lead chloride is a general term and can be used for either PbCl2 (Lead(II) chloride) or PbCl4 (Lead(IV) chloride), but it lacks specificity regarding the oxidation state of lead.
Thus, Lead(IV) chloride is the correct name for PbCl4, indicating the lead ion has an oxidation state of +4.