Question

Direction of electric dipole moment is from negative to positive charge why

Answer 1

As for the direction of dipole, it a convention such that dipole vector (when considered as a single entity) will always tend to align towards the direction of electric field and not away from it when left in any arbitrary position in the field. It is easy to see so as the torque on the dipole due to an external electric field is given by p⃗ ×E⃗ p→×E→. Not all people follow the same standards however. In chemistry textbooks, you will often see the dipole being directed towards the more electronegative atom. This was done probably because the electrons play a central role in any chemical interaction and dipole vector was a good indicator of where the electrons are more crowded. It is a pain to remember it sometimes, but we live with with it given the different nature of problems dealt in the two subjects.
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