Headaches are one effect that can come from inhalation of isopropyl alcohol. Isopropyl alcohol, or rubbing alcohol, is often used in the home or in medical facilities to treat various conditions or to sterilize instruments and skin. However, if isopropyl alcohol is inhaled there can be serious side effects.
1a) Definition of contradiction: A contradiction exists any time a proposition P is asserted to be true in conjunction with its negation, not-P. 1b) Definition of conjunction: A conjunction is a connective that joins two propositions.
These all seem to be contradictions because they seem either explicitly to state or logically imply a certain statement and its denial. (1) is an explicit contradiction. You can't love someone and not love someone at the same time. (2) is an implicit contradiction.