7848. The effectiveness factor for large value of Thiele modulus (L√(K/D1)) of a solid catalysed first order reaction is equal to (where, L = length of the reactor, cm, D1 = diffusion co-efficient, cm²/second) September 7, 2025 by Admin L√(K/D1) 1/(L√(K/D1)) 1 ∞ ✅ The correct answer is option B.