The compounds H1Cl and H2Cl are likely referring to different isotopes of hydrogen combined with chlorine. Let's examine the differences between them in terms of bond length and relative atomic mass.
H1Cl, or simply HCl, represents hydrogen chloride, where hydrogen is the protium isotope (the most common isotope of hydrogen with a single proton and no neutrons). HCl is a covalent compound and is a gas at standard temperature and pressure. The bond length in HCl is approximately 127 picometers (pm).
On the other hand, H2Cl refers to deuterium chloride (DCl). Deuterium is a hydrogen isotope with one proton and one neutron. Deuterium is stable and occurs naturally, although it is less abundant compared to protium. The presence of the heavier deuterium isotope affects the properties of the compound. The bond length in DCl is slightly longer compared to HCl, at around 130-132 pm. This increase in bond length is due to the larger mass of deuterium compared to protium.
In terms of relative atomic mass, H1Cl (HCl) has a relative atomic mass of approximately 36.46 atomic mass units (amu). This is because chlorine (Cl) has a relative atomic mass of about 35.45 amu, and hydrogen (H) has a relative atomic mass of approximately 1.01 amu.
H2Cl (DCl), on the other hand, has a slightly higher relative atomic mass. Deuterium (D) has a relative atomic mass of approximately 2.01 amu. Considering the relative atomic masses of deuterium and chlorine, the approximate relative atomic mass of DCl is around 37.47 amu.
To summarize, the differences between H1Cl (HCl) and H2Cl (DCl) lie in the isotopes of hydrogen present, resulting in a slightly longer bond length in DCl and a higher relative atomic mass for DCl compared to HCl.