Q.Which one of the following compounds is not formed?

Xenon is by far the most chemically reactive noble gas, owing to its comparatively low first ionisation energy. Direct reaction with fluorine gas over a nickel catalyst at 400 °C gives, depending on the Xe:F2 ratio and pressure, XeF2 (1:1), XeF4 (1:5, over Ni/acetone) or XeF6 (1:20, 200 atm). Heating XeF6 in a sealed quartz vessel at 50 °C progressively substitutes oxygen for fluorine via the quartz itself (2XeF6 + SiO2 -> 2XeOF4 + SiF4, then onward to XeO2F2, then XeO3); complete hydrolysis of XeF6 with water similarly gives the explosive solid XeO3 directly (XeF6 + 3H2O -> XeO3 + 6HF). Treating XeF6 with 2.5 M NaOH gives sodium perxenate (2XeF6 + 16NaOH -> Na4XeO6 + Xe + O2 + 12NaF + 8H2O), whose perxenate ion (XeO6^4-) is such a strong oxidant it converts Mn2+ directly to permanganate without a catalyst. Xenon also reacts directly with PtF6 to give the orange-yellow adduct [XePtF6] — historically the first noble-gas compound ever made (Bartlett, 1962) — and its fluorides act as fluoride-ion acceptors toward strong Lewis acids like SbF5/TaF5, forming add …