There are three different isotopes of hydrogen ¹H,²H,³H and three different isotopes of oxygen ¹⁶O,¹⁷O,¹⁸O.Indicate the number of different types of isotopically substituted water,H₂O,that could be formed. A)9 B)12 C)15 D)18

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With three isotopes of hydrogen and three isotopes of oxygen, the number of different isotopically substituted water molecules that can be formed is the product of the number of isotopes of each element, which is 3 hydrogen isotopes * 3 oxygen isotopes = 9. However, since water has two hydrogen atoms, we need to consider combinations of hydrogen isotopes as well. There are 3 choices for the first hydrogen atom and 3 choices for the second, giving 3 * 3 = 9 combinations of hydrogen alone. When combined with the 3 choices of oxygen isotopes, the total number of different isotopically substituted water molecules is 9 * 3 = 27. However, since the question specifies the formula as H2O, implying the consideration of each hydrogen isotope in combination with an oxygen isotope without distinguishing between the positions of the two hydrogen atoms (which would matter for molecules where the position could lead to different compounds, but not in the case of water due to its symmetrical nature), the correct interpretation should indeed reflect the basic combinations without overcounting for indistinguishable arrangements, leading to the initial calculation of 9 combinations of hydrogen (accounting for identical combinations as a single unique type due to the indistinguishable nature of the hydrogen atoms in water) and 3 of oxygen, which was an error in my explanation. The correct calculation, considering each hydrogen isotope can pair with each oxygen isotope and not overcounting identical hydrogen combinations, should indeed be 3 hydrogen isotopes * 3 oxygen isotopes = 9 unique types of water, which contradicts my initial conclusion. Therefore, the correct answer, based on the straightforward combination of available isotopes without overcomplicating the calculation, should be:AEach hydrogen isotope can combine with each oxygen isotope, resulting in 3*3 = 9 unique isotopically substituted water molecules.

There Are Three Different Isotopes of Hydrogen 1H,2H,3H and Three

There Are Three Different Isotopes of Hydrogen ¹H,²H,³H and Three