(2)Al+(3)F2=(2)AlF3
Al2O3+HF=(2)AlF3+(3)H2O
(3)Be<span> + </span><span>N2</span><span> → </span><span>Be3N2
</span>(3)BaH2+N2=Ba3N2+(3)H2
<span>CH3-NH-C2H5</span>
<span><span>CH2-CH2-CH2-CH-COOH</span></span>
I
CH3
Na2S2O8 + 2FeSO4 = Fe2(SO4)3 + Na2SO4