What year did the UN divide Palestine into a jewish state and an Arab state?

Answer 1

The Answer you are looking for is "the United Nations Partition Plan for the Mandate of Palestine".

However, there are two minor errors in the phrasing of this question. The first is semantic: the UN Partition Plan came out of UNGA Resolution 181 which was passed on November 29, 1947, not 1948. Israel declare independence according to the provisions of UNGA Resolution 181 on May 14, 1948, but that was not when the "division" occurred.

The second error is that Palestine was not actively divided. The UN took a map and made a prescriptive judgment about where a Jewish State should be and where an Arab State should be. It would have been binding had both sides agreed, but the Arabs were not interested in allowing for any Jewish State and therefore prevented an agreement from being realized. Therefore, Palestine was not actually divided physically, just potentially. Israel used this window of permissibility to declare statehood in 1948 and Palestine used this to declare statehood in 1988.

Answer 2

The phrasing of the question misconstrues the authority of the United Nations Resolution 181. Most people incorrectly believe that the UN Resolution "created" a Jewish State (Israel) and an Arab State (Palestine) on the map on November 29, 1947. This is not the case. What the UN Resolution does provide for is the permission for the different ethno-religious groups in Mandatory Palestine to declare a state. In the case of most mandates, the understanding was that the mandate would eventually become independent as one new state, like Iraq or Syria had. The case of Palestine was therefore unique and needed the permission to deviate from the traditional path of independence. Because of there being two states, provisional borders had to be provided, which is why a map was used, but those borders would only come into play if both sides decided to remain at peace.

The Jews acted on the permission granted to them by UN Resolution 181 by declaring independence on May 14, 1948 (nearly six months after the Resolution was passed) and therefore creating the State of Israel.