Romans 11:31-32 is a chiasm where vocabulary in the first section is used in reverse order in the second. The center, which is being emphasized, is that because of the mercy show to Gentiles, the Jews also may be shown mercy (v 31b-c). https://www.howthebiblefitstogether.org/files/Rom-11.31-32a-Chiasm.pdf
Romans 11:23-24 is a chiasm where vocabulary of the first section is repeated in reverse order in the second. The center, which is being emphasized, is that "you [Gentiles] were cut off from what is by nature a wild olive tree and were grafted contrary to nature into a cultivated olive tree" (vs 24a-b). https://www.howthebiblefitstogether.org/files/Rom-11.23-24a-Chiasm.pdf
Romans 11:11-14 is a chiasm where vocabulary of the first section is repeated in reverse order in the second, The climax is the center, "Now if their [the Jews'] transgression is riches for the world and their failure is riches for the Gentiles, how much more will their fulfillment be!" https://www.howthebiblefitstogether.org/files/Rom-11.11-14a-Chiasm.pdf
Romans 11:7 explains Romans 11:25 by showing that the partial hardening that has come upon Israel (v 25) means that elect within Israel obtained salvation but the rest were hardened (v 7). When the evangelization of the Gentiles has been completed (v 25), then all Israel will be saved at the second coming of Christ.