Supposing I am having 100 BTC in a single Bitcoin address and I send 1BTC to each individual ( total 100 individuals) and I have instantiated all of these transactions in one go( assuming that they will be running parallely). Also, assuming that it takes 10 minutes to validate a transaction, How much time will it take for the 100th transaction to be validated? Will the time depends on the previous unconfirmed transactions? ( Consider that there is no double spending here)
Assuming that by "validate" you mean "confirm" then a chain of 100 transactions sent from the same wallet should, theoretically, all confirm in the next block or two - assuming that each transaction's included fee is sufficient.
However, the outcome described above is only theoretical, because many clients place a relay limit on unconfirmed transactions in a single chain. The Core client, for example, does not accept more than 24 unconfirmed transactions from a single chain into its mempool.
In the case of your example chain of 100 transactions there could, therefore, be a best-outcome delay of at least 5 blocks before all the transactions are confirmed.
Further to your question, it is not a case that the 100th transaction is dependent on the 1st or the 99th transaction to have to confirm first. If each of the simultaneous 100 transactions being sent from a wallet is valid and has sufficient fees, then they will each be mined as individual valid transactions by miners, regardless of their wallet of origin. If a miner happens to be running the Core client, then there will be a batch limit of 24 transactions (from the single chain) that can be mined per block.
As pointed out in the comments, a transaction can have more than one output, so your example's 100 recipients can each be sent bitcoin via a single transaction.