Stereo Projections Checker — CIP Priority & Rotation
Practice CIP-priority comparisons and the frequently-misunderstood distinction between (R)/(S) configuration and (+)/(−) optical rotation, checked against the same live CIP engine used throughout this site.
Which substituent has HIGHER CIP priority: OH or NH2?
OH. The very first atom decides it: O (atomic number 8) outranks N (7). No need to look any further.
An (R) configuration always rotates plane-polarized light clockwise, i.e. is always (+).
False. (R)/(S) is a STRUCTURAL label from the CIP priority rules — pure geometry. (+)/(−) is an experimentally MEASURED property (which way a polarimeter shows light rotating). They are not derived from each other: some (R) compounds are (+), some are (−), and you cannot tell which just by looking at the structure.
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