JAMB - Chemistry (2000 - No. 32)
The substance often used for vulcanization of rubber is
chlorine
hydrogen peroxide
sulphur
tetraoxosulphate (IV) acid
Vysvetlenie
Vulcanization is a process that involves heating rubber with sulphur to improve its strength and elasticity. The process is carried out by mixing latex with sulphur and heating it. Other vulcanizing agents, like selenium and tellurium, are sometimes used, but sulphur is the most common.