How would you convert ethene into ethane ?

Give the formula and names of A, B, C and D in the following equation :

${\mathrm{CH}}_4\underset{-\mathrm{HCl}}{\overset{{\mathrm{Cl}}_2}{\to }}\mathrm{A}\underset{-\mathrm{HCl}}{\overset{{\mathrm{Cl}}_2}{\to }}\mathrm{B}\underset{-\mathrm{HCl}}{\overset{{\mathrm{Cl}}_2}{\to }}\mathrm{C}\underset{-\mathrm{HCl}}{\overset{{\mathrm{Cl}}_2}{\to }}\mathrm{D}$

Give the formula and names of A, B, C and D in the following equation :

${\mathrm{C}}_2{\mathrm{H}}_2\stackrel{{\mathrm{H}}_2}{\to }\mathrm{A}\stackrel{{\mathrm{H}}_2}{\to }\mathrm{B}\underset{-\mathrm{HBr}}{\overset{{\mathrm{Br}}_2}{\to }}\mathrm{C}\underset{-\mathrm{HBr}}{\overset{{\mathrm{Br}}_2}{\to }}\mathrm{D}$

Give the formula and names of A, B, C and D in the following equation :

${\mathrm{C}}_2{\mathrm{H}}_4+\mathrm{B}\underset{\mathrm{Ni}}{\overset{200°\mathrm{C}}{\to }}{\mathrm{C}}_2{\mathrm{H}}_6$

Write the name and formula of the product formed in the case below :

${\mathrm{C}}_2{\mathrm{H}}_4+{\mathrm{Cl}}_2\to$