An element X, turns a volatile hydride XH 3 with a density of 17.2. The

Explanation

An element X reacts with a volatile hydride XH 3 that has a density of 17.2. The question is asking for the relative atomic mass of element X. When an element reacts with a volatile hydride, the density of the hydride can be used to determine the relative atomic mass of the element. The higher the density of the hydride, the higher the relative atomic mass of the element. Therefore, the correct answer is Option A: 34.0. This is because out of all the options listed, Option A has the highest relative atomic mass, which matches the pattern described above. It is important to note that the relative atomic mass of an element is the average mass of all the isotopes of that element, taking into account their abundance. Isotopes are atoms of the same element with different numbers of neutrons. To learn more about this, please read the relevant sections of the recommended textbooks