Tax on CG

A is the seller of the property so buyer will pay only to A. Even if the buyer agrees to pay 5L to A and balance 5L to A's friend, it will still be considered as full income earned by A and then utilised and given to A's friend. it is called application of income. Generally, such payment by A to his friend directly or indirectly will be taxed in the hands of A's friend as a Gift from Non-Relative taxable under the head Income from Other Sources. Unfortunately, A will pay tax on 4 lakhs and A's friend will pay tax on 5 lakhs.

Can A gift half of the property to A's friend before selling to avoid double taxation?

The  stamp duty value of the property gifted will still be taxed to A's friend

Gift of the property will also be liable to tax because its gift to a nonrelative.