AP EAPCET 6 Sep 2021 Shift 1 Paper

Which statements about Boron and its compounds, among the following, are true?
(i) Boron has high density and good electrical conductivity.
(ii) ‌10B isotope metal borides are useful as protective shields in nuclear industry.
(iii) Borax and boric acid are used in the manufacture of glasses.
(iv) Orthoboric acid is toxic and hence not usefil in antiseptic solutions.