KEAM 2011 Physics and Chemistry Paper

(i) Be and Al both react with HCl to liberate H2.
Be+2HCl⟶BeCl2+H2↑
2Al+6HCl⟶2AlCl3+3H2↑
(ii) Be renders passive with conc. HNO3 and so does not react. Conc.HNO3 is strong oxidising agent and forms very thin layer of oxide on the surface of metal. Similarly, Al become passive in conc. HNO3 due to formation of oxide layer on the surface.
(iii) Their carbides gives methane on treatment with water.
Be2C+4H2O⟶2Be(OH2)+CH4
(iv) Their oxides, BeO and Al2O3 are amphoteric.