The second problem needs to regard hydrogen ions as the neutralization of+18e and-17e, otherwise it cannot be calculated by the electric moment formula. Let the distance between the center of negative charge and hydrogen ion be x, and the dipole with molecular electric moment of +- 18e and the dipole with +- 17e produce the vector sum of electric moments.

18e x-17e * 0.128 = 3.4 *10-21nm, so x=0. 122 1nm. Pay attention to the exact value1.602 *10-19 c when calculating e, otherwise there will be a big error.

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