= Solution
For ideal freely mobile <counterions>, their gross <osmotic pressure> is
$$
\boxed{\Pi=\frac{Nk_BT}{V_c}=4.94\times10^6\,\mathrm{Pa}\simeq49\,\mathrm{bar}\quad(T=300\,\mathrm K).}
$$
If the <DNA> volume is excluded from the ion-accessible <volume>, use $V_f=V_c-V_D$ instead, giving $\Pi\simeq1.23\times10^7\,\mathrm{Pa}\simeq123\,\mathrm{bar}$. These are ideal-ion estimates; bound <counterions> contribute less like independent mobile particles, and the net outward <osmotic pressure> also subtracts the external osmotic contribution.
Stored <free energy> associated with this <pressure>, together with bending and interstrand repulsion, can favor initial genome release when a delivery pathway becomes available. This explains a possible mechanical benefit of dense packaging at a conceptual level. It does not imply that internal <pressure> necessarily supplies all the <work> of complete genome delivery into a host, whose own environment and interactions also matter.
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