Given, three capacitors P,Q and R.Charge acquired by the capacitor when, P is charged to a potential difference V is, Q=CV.i) When P is connected to Q in parallel : total capacitance -C=C1+C2 = 2Ctotal charge on two capacitors=q+0=q=CV∴ potential difference between the plates of P= CV2C=V2ii) When P is connected to R in series :On such a connection, the circuit will not be completed. And hence, the sharing of charges will not take place. So, the potential will remain as V. That is, it remains unchanged.