THE QUANTITATIVE ELECTROPHILIC REACTIVITY OF ANNULENES .2. PARTIAL RATE FACTORS FOR HYDROGEN-EXCHANGE OF AZULENE, CYCL[3,2,2]AZINE, INDOLIZINE, N-METHYLISOINDOLE, INDOLE, AND PYRROLO[2,1-B]THIAZOLE, AND ATTEMPTED EXCHANGE IN TRANS-9,10-DIMETHYLDIHYDROPYRENE - THE DRAMATIC EFFECT OF CREATING AROMATICITY IN THE TRANSITION-STATE FOR ELECTROPHILIC SUBSTITUTION, AND THE IMPORTANCE OF VALENCE BOND THEORY-