Electronegativity and bond polarityAQA A-Level Chemistry: Mind map

Exam questions on Electronegativity and bond polarity

1. Hydrogen chloride, HCl, is a gas that dissolves in water to form hydrochloric acid. The two atoms in an HCl molecule share one pair of electrons, and chlorine is more electronegative than hydrogen.
   Explain why the bond in HCl is polar.2 marks
2. Carbon dioxide, CO₂, and sulfur dioxide, SO₂, both contain polar bonds between oxygen and a central non-metal atom. Oxygen is more electronegative than both carbon and sulfur. A CO₂ molecule is linear, whereas an SO₂ molecule is bent.
   Explain why SO₂ has a permanent dipole but CO₂ does not.2 marks
3. Chlorine is found in several molecules, including chlorine gas, Cl₂, tetrachloromethane, CCl₄, and trichloromethane, CHCl₃. Pauling electronegativity values are 2.5 for carbon, 2.1 for hydrogen and 3.0 for chlorine.
   Explain why the bond in Cl₂ is non-polar but the C–Cl bond in CCl₄ is polar, stating the partial charge on each atom in C–Cl.3 marks