Initially, when both bulbs are at 273 K. The mole in each bulb,
=Total mole2=P.2V2RT=PVRT=76×VR×273
On heating second bulb some mole of gas is transferred to the bulb.
For bulb 1n1=P1×VR×273
For bulb 2n1=P2×VR×335
Since n=n1+n2
∴76×VR×273×2=P1×VR×273+P2×VR×335
Also P1=P2
∴P1=83.75cmHg