Does the prayer become invalid if alcohol from another person's perfume splashes onto one, and does moral impurity necessitate repeating ablution or invalidate the prayer, or is it a sin in itself?

Sitting next to someone who has applied perfume does no harm, nor does impurity transfer merely by smelling a scent. As for spiritual impurity, such as the impurity of disbelievers — according to scholarly verification — it does not invalidate ablution or prayer. There is no sin in shaking hands with them or eating with them. The questioner is advised to learn what scholars establish, without delving with his own mind into matters he is not proficient in, as this could lead to significant errors.