Chemical Reaction Engineering MCQs 2026

Elementary rate law r = k C_A^n implies

1. A equilibrium constant ✓
2. B extent of reaction only ✓
3. C heat transfer coefficient ✓
4. D reaction order n with respect to A ✓

Langmuir-Hinshelwood mechanism applies to

1. A only gas-phase chain reactions ✓
2. B only enzyme in solution without surface ✓
3. C only distillation trays ✓
4. D surface reaction on catalyst with adsorption steps ✓

Mixed flow reactor exit conversion for first-order liquid reaction is

1. A X = kτ/(1+kτ) ✓
2. B X = 1 − exp(−kτ) for PFR ✓
3. C X = kτ always linear ✓
4. D X = 0 always ✓

Half-life for first-order reaction t_1/2 equals

1. A 1/k ✓
2. B k/2 ✓
3. C 0.693/k ✓
4. D 2/k ✓

Damköhler number compares

1. A reaction rate to transport rate ✓
2. B heat to work ✓
3. C pressure to gravity ✓
4. D molecular weight to density only ✓

Thiele modulus relates

1. A only external film only ✓
2. B only pump head ✓
3. C only distillation reflux ✓
4. D reaction rate in pellet to diffusion rate inside pellet ✓

Space time τ in PFR is

1. A F/V always called residence without volume ✓
2. B only catalyst weight ✓
3. C only heat duty ✓
4. D V/F_total for volumetric basis ✓

PFR model assumes

1. A complete backmixing ✓
2. B zero flow ✓
3. C fluid elements move in series without mixing axially ✓
4. D only batch operation ✓

CSTR characteristic is

1. A plug flow with no mixing ✓
2. B no volume holdup ✓
3. C only solid catalyst fixed bed without fluid ✓
4. D well-mixed contents with uniform composition ✓

Arrhenius equation k = A exp(−E/RT) shows rate constant increases with

1. A pressure only always ✓
2. B catalyst pore length only ✓
3. C temperature ✓
4. D reactor diameter only ✓