The question does not make sense. Geographical features do not have antonyms.
beach
The Persian gulf
PHYSICAL FEATURES are the properties of how something looks.
Iran is a country on the Persian Gulf.
Kuwait is a country in the Persian Gulf
The Persian Gulf
Bahrain is an island country in the Persian Gulf and the smallest country in the Persian Gulf area.
The other name for the Persian Gulf is the Arabian Gulf
NO, the Sinai Peninsula is far to the west of Persian Gulf. It is the Omani Peninsula which separates the Persian Gulf and the Gulf of Oman.
The only body of water that borders Iraq is the Persian Gulf.
Bahrain is an archipelago of islands completely surrounded by the Persian Gulf.