The statement that is true about the chemical species represented by 2H2 15H 7 is that it refers to a specific isotope of hydrogen. In this notation, ‘2H’ denotes deuterium, which is an isotope of hydrogen that contains one proton and one neutron in its nucleus, while ’15H’ corresponds to tritium, another isotope that has one proton and two neutrons.
This representation also points to the fact that these isotopes have different atomic masses compared to regular hydrogen (1H) which contains only one proton and no neutrons. Consequently, any compound involving these isotopes will have distinct physical and chemical properties compared to those composed solely of regular hydrogen.