In the given circuit diagram when the current reaches steady state in the circuit, the charge on the capacitor of capacitance C will be :

At steady state, no current will flow through the capacitor.
Current through the battery: i = E/(r + r2)
Potential diff. across P2: V = ir2
V = Er2/(r + r2)
Thus charge on capacitor: Q = CV
Q = CEr2/(r + r2)