Question

Complete reaction `PbO+C ->Pb+?` Some sources suggest `CO_2` while others `CO`. Do they exist in equilibrium?

Answer 1

This describes the reaction when lead oxide is heated in a furnace with charcoal. Both probably result, but more sources mention carbon dioxide than carbon monoxide.

Hence,

`2PbO(s) + C(s) rightleftharpoons 2Pb(s) + CO_2(g)`

or

`PbO(s) + CO(g) rightleftharpoons Pb(s) + CO_2(g)`

are more representative of what's happening.

And, regarding equilibrium: every reaction is in equilibrium, but some lie so far toward one side they are simplified with one arrow. I would hypothesize that this reaction proceeds backwards at such a slow rate we can represent the reaction with a one-way arrow.