The dipole moment is given by μ = qr, where q is the charge separated (in C) and r is the distance separating the charge. Since we're given the dipole moment (1.21 D) and the bond length (2.49 Angstrom), we solve for the charge q. Dipole moments are given in D units - recall that 1 D = 3.34 x 10^{-30} C-m. We convert the bond length into meters: