When a carbon compound combines with another compound to form a product containing all of the atoms in both reactants, this is referred to as-

When a carbon compound combines with another compound to form a product containing all of the atoms in both reactants, this is referred to as an addition reaction.

For example- The hydrogenation of vegetable oils is an example of an addition reaction, In which hydrogen is added to unsaturated vegetable oil in presence of a catalyst to convert it into a saturated compound. The reaction is followed as-

$\mathrm{RCH}=\mathrm{CHR}+ {\mathrm{H}}_{2 }\stackrel{\mathrm{Ni}}{\to } {\mathrm{RCH}}_2-{\mathrm{CH}}_2\mathrm{R}$