Answer :
-1 is the answer
So it requires one cation (i.e. positively charged ion). So according to this, its valency is -1. A hydrogen carbonate ion has the formula HCO3-, so the valency of a hydrogen carbonate ion is -1.
So it requires one cation (i.e. positively charged ion). So according to this, its valency is -1. A hydrogen carbonate ion has the formula HCO3-, so the valency of a hydrogen carbonate ion is -1.