Which of the following is most polar bond ?

Which of the following is the most polar bond

The electronegativity values of C, H, O and N are 2.5, 1.0, 3.0 and 3.5 respectively: Which of the following is the most polar bond?

Which of the following is the most polar?

Which of the following bonds is most polar ?

Which of the following bonds is most polar ?

Which of the following has both polar and non-polar covalent bonds ?

Which of the following is non-polar but contains polar bonds?

Which of the following is non-polar but contains polar bonds?