Bitcoins can not be distinguished between each other. Actually there are no bitcoins. There is only a "quantity" you have and this quantity is refered as "Bitco

Bitcoins can not be distinguished between each other. Actually there are no bitcoins. There is only a "quantity" you have and this quantity is refered as "Bitcoin". You do not have any control over how you sent/spend bitcoin quantities. So If you have 2 bitcoins you can not number these as first bitcoin and second bitcoin. But if you look into the minted bitcoins, yes these are possible. But they are not the currency in flow. They are special things.