Vulcanization Is basically a chemical process where the rubber is treated with sulphur and heated to a greater extent to improves its properties like elasticity and to harden it. So now when we observe the options we see that option I and iv go very well with the definition. Vulcanized rubber is soluble in organic solvents, one of the reasons of vulcanization is also the betterment of solubility of rubber in organic solvents hence option ii stays false. Vulcanization makes rubber. A crystalline solid neither expands on heating nor contracts on cooling, which is converse to the property shown by the vulcanized rubber. Hence we prove that point iii stays false.