Question

Why cant lead (ii) chloride be prepared by action of dilute hydrochloric acid on lead(ii) carbonate?

Answer 1

Lead(II) chloride can be prepared by the action of dilute hydrochloric acid on lead(II) carbonate.

Explanation:

`"PbCO"_3("s") + "2HCl(g)"` `rarr` `"PbCl"_2("s") + "H"_2"CO"_3("aq")"`

Carbonic acid `("H"_2"CO"_3)` is unstable and decomposes:

`"H"_2"CO"_3("aq")"` `rarr` `"H"_2"O("l") + CO"_2("g")"`

The overall reaction is:

`"PbCO"_3("s") + "2HCl(g)"` `rarr` `"PbCl"_2("aq") + "H"_2"O("l") + CO"_2("g")"`

Answer 2

It cannot be prepared like this because it is insoluble.

Explanation:

There may a slight reaction but because lead(II) chloride is insoluble it forms on the surface of the lead(II) carbonate and inhibits further reaction.

The standard way to prepare an insoluble salt is by precipitation.

You need to start with two suitable soluble reagents such as lead(II) nitrate and sodium chloride solution.

`sf(Pb(NO_3)_(2)(aq)+2NaCl(aq)rarrPbCl_2(s)` `sf(+2NaNO_3(aq))`

The mixture is filtered and the residue washed and dried.