In a series RC circuit, does the resistor voltage lag the current?
Resistor voltage is in phase with the total current.
If its a DC source, then it is neither leading nor lagging.
If its an ac source, then the circuit is capacitive overall (since no inductor present) and so total current leads total voltage. (leading power factor).
However, on a phasor diagram, resistor voltage has same phase angle as total current (