When metals such as sodium react with an acid, a salt and hydrogen gas is produced. and we know for sure the oxidation state of sodium in the compound will be +1. But for other metals such as iron, when they rest with acids which oxidation state do I use? I'm unsure if I'm supposed to use the lowest oxidation first as when iron reacts with an acid its oxidation state is +2 first. But for other metals which one do I use first such as copper? Thanks for. The help guys!