Натрий. Ему проще всего отдать электрон.
A)1)2CH4=C2H2+3H2;
2)3C2H2=C6H6
3)C6H6+Cl2=C6H5Cl+HCl
C2H6+Br2=C2H5Br+HBr
C2H5Br+KOH=C2H5OH+KBr
3C2H5OH<span> + </span>K2Cr2O7<span> + 4</span>H2SO4<span> → </span>Cr2(SO4<span>)3 + </span><span>3CH3CHO + </span>K2SO4<span> + </span>7H2O<span>
</span>CH3CHO+H2=C2H5OH
2C2H5OH=CH2=CH-CH=CH2+2H2O+H2