JAMB - Chemistry (2015 - No. 4)
In the industrial production of H2 from water gas the CO2 produced along with the H2 is removed by
washing under pressure
drying over phosphorus (V) oxide
passing the mixture to the limewater
using ammonical copper (I) chlorine
Explication
Washing under pressure is an action in the industrial production of H. Options B,C,D will not yield Co and H