Volume occupied by B atom =20% of total volume =20%‌ of ‌22.7L‌=4.54L ‌ Remaining volume ‌‌=(22.7−4.54)L ‌=18.16L Mole fraction of B=χB=‌
4.54
22.7
=0.2 Mole fraction of B2=χB2=‌
18.16
22.7
=0.8 Partial pressure of B=pB=0.2×1=0.2 bar Partial pressure of ‌B2=pB2=0.8×1=0.8‌ bar ‌ ‌‌‌Kp=‌