I am using Mycelium wallet to store btc. Does this wallet has private key? All I found is call seed. Does "master seed" is equal to "private key"? i am trying to receive airdrop of Bitcoin Private, is Mycelium able to to get this airdrop?
a seed is not equal to a private key.
Basically, a seed is used to calculate a "master private key". Given a certain derivation path, "normal" private keys are derived from this "master private key". This is the short (easy) version, but as a normal user, you shouldn't worry about the technical part to much... Your wallet will take care of all these calculations and derivations for you. The only thing you should remember is that if you remember which wallet software you used, and you've written down the seed, there'll almost always be a way to restore your wallet if your pc crashes, or you accidentally delete your wallet.
I have never heared about Bitcoin Private,
but i would like to warn you about airdrops that require you to share your seed, xprv or any other private key (i mean, really, these keys have the word
private right in their name, it should be obvious they're not meanth for sharing).... These airdrops are *usually* scams that are started to collect private keys from unsuspecting victims in order to rob them later...
If you accidentally already submitted your seed to anybody, i'd suggest you to create a new, clean wallet, and move your funds ASAP, treat the old wallet as compromised and never use it again...