Chemical Engineering GATE 2011 Questions with Answer

Ques 1 Chemical Engineering Thermodynamics

Minimum work (W) required to separate a binary gas mixture at a temperature T₀ and pressure P₀ is W=-RT₀[y₁ln( f0₁/f_pure,1)+y₂ln( f0₂/f_pure,2)] where y₁ and y₂ are mole fractions, f_pure,1 and f_pure,2 are fugacities of pure species at T₀ and P₀, and f0₁ and f0₂ are fugacities of species in the mixture at T₀ P₀ and y₁. If the mixture is ideal then W is

Ques 2 Chemical Engineering Thermodynamics

The partial molar enthalpies of mixing (in J/mol) for benzene (component 1) and cyclohexane (component 2) at 300 K and 1 bar are given by Δ‾H₁=3600x₂² and Δ‾H₂=3600x₁², where x₁ and x₂ are the mole fractions. When ONE mole of benzene is added to TWO moles of cyclohexane, the enthalpy change (in J) is

Ques 3 Chemical Engineering Thermodynamics

One mole of methane is contained in a leak proof piston-cylinder assembly at 8 bar and 1000 K. The gas undergoes isothermal expansion to 4 bar under reversible conditions. Methane can be considered as an ideal gas under these conditions. The value of universal gas constant is 8.314 J mol^-1K^-1. The heat transferred (in kJ) during the process is

Ques 4 Chemical Engineering Thermodynamics

Consider a binary mixture of methyl ethyl ketone (component 1) and toluene (component 2). At 323 K the activity coefficients γ₁ and γ₂ are given by
ln γ₁=x₂²(ψ₁-ψ₂+4ψ₂x₁)
ln γ₂=x₁²(ψ₁+ψ₂-4ψ₂x₂)
where x₁ and x₂ are the mole fractions in the liquid mixture, and ψ₁ and ψ₂ are parameters independent of composition. At the same temperature, the infinite dilution activity coefficients, γ₁^∞ and γ₂^∞ are given by lnγ₁^∞=0.4 and lnγ₂^∞=0.2. The vapour pressures of methyl ethyl ketone and toluene at 323 K are 36.9 and 12.3 kPa respectively. Assuming that the vapour phase is ideal, the equilibrium pressure (in kPa) of a liquid mixture containing 90 mol % toluene is

Ques 5 Chemical Reaction Engineering

In an aqueous solution, reaction P→Q occurs under isothermal conditions following first order kinetics. The feed rate is 500 cm³/min and concentration of P in the feed is 1.5×10^-4mol/cm³. The reaction is carried out in a 5 litre CSTR. At steady state, 60% conversion is observed. The rate constant (in min^-1) is

Ques 6 Chemical Reaction Engineering

In an aqueous solution, reaction P→Q occurs under isothermal conditions following first order kinetics. The feed rate is 500 cm³/min and concentration of P in the feed is 1.5×10^-4mol/cm³. The reaction is carried out in a 5 litre CSTR. At steady state, 60% conversion is observed. The 5 litre CSTR is replaced by five CSTRs in series. If the capacity of each new CSTR is 1 litre, then the overall conversion (in %) is

Ques 7 Chemical Reaction Engineering

Consider an irreversible, solid catalysed, liquid phase first order reaction. The diffusion and the reaction resistances are comparable. The overall rate constant (k_o) is related to the overall mass transfer coefficient (k_m) and the reaction rate constant (k) as

Ques 8 Chemical Reaction Engineering

Reactant R forms three products X, Y and Z irreversibly, as shown below.
R → X, Y, Z
The reaction rates are given by r_X=k_XC_R, r_Y=k_YC_R^1.5 and r_Z=k_ZC_R. The activation energies for formation of X, Y and Z are 40, 40 and 5 kJ/mol respectively. The pre-exponential factors for all reactions are nearly same. The desired conditions for MAXIMIZING the yield of X are

Ques 9 Chemical Reaction Engineering

For a first order catalytic reaction the Thiele modulus (φ) of a spherical pellet is defined as φ=(R_s/3)√(kρ_p/D_e) where ρ_p=pellet density, D_e=effective diffusivity, R_s=pellet radius, k=first order reaction rate constant. If φ>5, then the apparent activation energy (E_a) is related to the intrinsic (or true) activation energy (E) as

Ques 10 Chemical Reaction Engineering

The following figures show the outlet tracer concentration profiles (c vs. t) for a pulse input.

Ques 11 Chemical Technology

Match the reactions in Group I with the products in Group II.
GROUP I
P. Ammoxidation
Q. Nitration
R. Dehydrogenation
S. Oxidation
GROUP II
I. Aniline from benzene
II. Benzoic acid from toluene
III. Acrylonitrile from propylene
IV. Styrene from ethylbenzene

Ques 12 Chemical Technology

Match the polymerisation mechanisms in Group I with the corresponding polymers in Group II
GROUP I
P. Chain growth/addition polymerisation
Q. Step growth/condensation polymerisation
GROUP II
I. Polyethylene
II. Polyvinyl chloride
III. Polyethylene terephthalate

Ques 13 Chemical Technology

Which ONE of the following sequences is arranged according to INCREASING calorific value?