Cyclohexane (C6H12) is produced from benzene (C6H6) and hydrogen (H2): C6H6 + 3H2 → C6H12. Overall and single-pass conversions are 90% and 25%, respectively. The recycle stream contains 25 mol% C6H6 and 75 mol% H2. If the fresh feed contains 25% excess H2, at steady state, the ratio of the molar flow rate of recycle stream to that of the fresh feed is _________ (rounded off to one decimal place).

Question

Accepted Answer

The correct answer is 2.1 to 2.3. GATE 2026 official key: 2.1 to 2.3. Basis fresh feed=100 mol (21.05 C6H6, 78.95 H2, 25% excess H2). Reactor C6H6 reacted = 0.25×(21.05+0.25R) = 0.9×21.05 gives R ≈ 218.9, so R/F ≈ 2.19.