Chemical Engineering GATE 2024 Questions with Answer

Ques 53 General Aptitude

In the 4 × 4 array shown below, each cell of the first three columns has either a cross (X) or a number, as per the given rule.

Ques 54 Heat Transfer

If the Prandtl number Pr = 0.01, which of the following statements is/are correct?

Ques 55 Heat Transfer

The opposite faces of a metal slab of thickness 5 cm and thermal conductivity 400 W m⁻¹ ℃⁻¹ are maintained at 500 ℃ and 200 ℃. The area of each face is 0.02 m². Assume that the heat transfer is steady and occurs only in the direction perpendicular to the faces. The magnitude of the heat transfer rate, in kW, rounded off to the nearest integer, is __________

Ques 56 Heat Transfer

he temperatures of two large parallel plates of equal emissivity are 900 K and 300 K. A reflection radiation shield of low emissivity and negligible conductive resistance is placed parallelly between them. The steady-state temperature of the shield, in K, is

Ques 57 Heat Transfer

Hot oil at 110 ℃ heats water from 30 ℃ to 70 ℃ in a counter-current double-pipe heat exchanger. The flow rates of water and oil are 50 kg min⁻¹ and 100 kg min⁻¹, respectively, and their specific heat capacities are 4.2 kJ kg⁻¹ ℃⁻¹ and 2.0 kJ kg⁻¹ ℃⁻¹, respectively. Assume the heat exchanger is at steady state. If the overall heat transfer coefficient is 200 W m⁻² ℃⁻¹, the heat transfer area in m² is __________

Ques 58 Heat Transfer

A solid slab of thickness H₁ is initially at a uniform temperature T₀. At time t = 0, the temperature of the top surface at y = H₁ is increased to T₁, while the bottom surface at y = 0 is maintained at T₀ for t ≥ 0. Assume heat transfer occurs only in the y-direction, and all thermal properties of the slab are constant. The time required for the temperature at y = H₁/2 to reach 99% of its final steady value is τ₁. If the thickness of the slab is doubled to H₂ = 2H₁, and the time required for the temperature at y = H₂/2 to reach 99% of its final steady value is τ₂, then τ₂ / τ₁ is ______

Ques 59 Mass Transfer

Consider the steady, uni-directional diffusion of a binary mixture of A and B across a vertical slab of dimensions 0.2 m × 0.1 m × 0.02 m as shown in the figure. The total molar concentration of A and B is constant at 100 mol m⁻³. The mole fraction of A on the left and right faces of the slab are maintained at 0.8 and 0.2, respectively. If the binary diffusion coefficient D_AB = 1 × 10⁻⁵ m² s⁻¹, the molar flow rate of A in mol s⁻¹, along the horizontal x direction is

Ques 60 Mass Transfer

Consider a vapour-liquid mixture of components A and B that obeys Raoult’s law. The vapour pressure of A is half that of B. The vapour phase concentrations of A and B are 3 mol m⁻³ and 6 mol m⁻³, respectively. At equilibrium, the ratio of the liquid phase concentration of A to that of B is

Ques 61 Mass Transfer

Which one of the given statements is correct with reference to gas-liquid contactors for mass transfer applications?

Ques 62 Mass Transfer

A gas stream containing 95 mol% CO₂ and 5 mol% ethanol is to be scrubbed with pure water in a counter-current, isothermal absorption column to remove ethanol. The desired composition of ethanol in the exit gas stream is 0.5 mol%. The equilibrium mole fraction of ethanol in the gas phase, y^*, is related to that in the liquid phase, x, as y^* = 2x. Assume CO₂ is insoluble in water and neglect evaporation of water. If the water flow rate is twice the minimum, the mole fraction of ethanol in the spent water is ______

Ques 63 Mass Transfer

Sulfur dioxide (SO₂) gas diffuses through a stagnant air-film of thickness 2 mm at 1 bar and 30 ℃. The diffusion coefficient of SO₂ in air is 1 × 10⁻⁵ m² s⁻¹. The SO₂ partial pressures at the opposite sides of the film are 0.15 bar and 0.05 bar. The universal gas constant is 8.314 J mol⁻¹ K⁻¹. Assuming ideal gas behavior, the steady-state flux of SO₂ in mol m⁻² s⁻¹ through the air-film is ______

Ques 64 Mass Transfer

A simple distillation column separates a binary mixture of A and B. The relative volatility of A with respect to B is 2. The steady-state composition of A in the vapour leaving the 1^st, 2^nd and 3^rd trays in the rectifying section are 94, 90 and 85 mol%, respectively. For ideal trays and constant molal overflow, the reflux-to-distillate ratio is ______