To calculate the electronegativity difference between hydrogen H and chlorine Cl in the HCl molecule, we need to know the electronegativity values of both elements. The electronegativity values are based on the Pauling scale.The electronegativity of hydrogen H is 2.1, and the electronegativity of chlorine Cl is 3.16.Now, we can calculate the electronegativity difference:Electronegativity difference = | Electronegativity of Cl - Electronegativity of H |Electronegativity difference = | 3.16 - 2.1 |Electronegativity difference = 1.06So, the electronegativity difference between hydrogen and chlorine in the HCl molecule is 1.06.