Solution:
Zirconium is non-radioactive. It is a chemical element with the symbol Zr, atomic number 40 and atomic mass of 91.224. The name of zirconium is taken from the mineral zircon, the most important source of zirconium. It is a lustrous, grey-white, strong transition metal that resembles titanium. Zirconium is mainly used as a refractory and opacifier, although minor amounts are used as alloying agent for its strong resistance to corrosion.

Solution:
Nitrogen forms a variety of compounds in all oxidation states ranging from –3 to +5.

Solution:
Water-gas A mixture of carbon monoxide (CO) and hydrogen (H2) produced by passing steam over red-hot coke using the endothermic reaction.

Solution:
Caffeine (C8H10N4O2) is a bitter alkaloid found especially in coffee, tea, cacao, and kola nuts.

Solution:
Domestic cooking gas consists mostly of Liquified butane and isobutane.

Solution:
In order to give more strength and more elasticity, natural rubber is heated with sulphur or sulphur compounds at 150°C temperature. Vulcanized rubber has good tensile strength. The working temperature of vulcanized rubber is enhanced up to 100°C. It has good resistance to organic solvents.

Solution:
Al2O3 is most acidic.