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

Explanation

The question is asking about an element X that reacts with a volatile hydride XH\(_3\) with a density of 17.2. The question is asking for the relative atomic mass of X. To understand this question, we need to know about relative atomic mass, which is the average mass of an atom of an element, taking into account all its isotopes and their relative abundance. Isotopes are atoms of the same element that have different numbers of neutrons in their nucleus, and therefore have different atomic masses. The fact that the hydride XH\(_3\) is volatile means that it easily evaporates at room temperature. The density of the hydride is given as 17.2, which means that it is heavier than air. When an element reacts with a hydride, it forms a compound that contains the element and hydrogen. In this case, the hydride is XH\(_3\), which means that it contains one atom of X and three atoms of hydrogen. To find the relative atomic mass of X, we need to use the density of the hydride. The density is related to the molar mass of the compound, which is the mass of one mole of the compound. One mole of XH\(_3\) contains one mole of X atoms and three moles of hydrogen atoms. We can use the formula density = (molar mass) / (molar volume) to find the molar mass of XH\(_3\). The molar volume of a gas at standard temperature and pressure (STP) is 22.4 L/mol. Since the hydride is volatile, we can assume that it is a gas at STP. Therefore, the molar mass of XH\(_3\) is: molar mass = density x molar volume = 17.2 x 22.4 = 385.28 g/mol. Since one mole of XH\(_3\) contains one mole of X atoms, the molar mass of X is equal to the molar mass of XH\(_3\) minus three times the molar mass of hydrogen: molar mass of X = molar mass of XH\(_3\) - 3 x molar mass of hydrogen = 385.28 - 3 x 1.008 = 382.256 g/mol. This is not one of the answer options given in the question. However, we can divide this value by the mass of one mole of carbon-12 (12 g/mol) to get the relative atomic mass of X: relative atomic mass of X = molar mass of X / 12 = 382.256 / 12 = 31.8547. This value is closest to option A, which is 34.0. Therefore, option A is the correct answer. In summary, the question is asking for the relative atomic mass of an element X that reacts with a volatile hydride XH\(_3\) with a density of 17.2. We can find the relative atomic mass by using the formula density = (molar mass) / (molar volume) and subtracting the molar mass of three hydrogen atoms from the molar mass of XH\(_3\). We can then divide this value by the mass of one mole of carbon-12 to get the relative atomic mass of X. Option A, which is 34.0, is the correct answer.