What will be the length of the gas column AB when the tube is held vertically with the end D up? — States of Matter and Gaseous State Chemistry Question

💡 Solution & Explanation

When held vertically with 'D' up, let the mercury column move toward A by x cm. The upper column CD becomes (60 + x) cm, and the lower column AB becomes (20 - x) cm. Applying Boyle's Law: P_D = P0 × 60 / (60 + x), and P_A = P0 × 20 / (20 - x). Force balance: P_A = P_D + 20 → 37.5 × 20 / (20 - x) = 37.5 × 60 / (60 + x) + 20. Solving this equation for x yields x ≈ 6.12 cm. The length of AB is 20 - 6.12 = 13.88 cm.