⚗️ Chemical Engineering Solved MCQs with Answers

Practice 1920 approved ⚗️ Chemical Engineering questions with verified answers from the 🛠️ Engineering Essentials subject for Pakistan exams.

1920 solved MCQs

Pick out the correct statement about the condensation.Answer: Suitable coating or vapour additive is used to promote film wise condensation. Pick out the wrong statement pertaining to the design of the bubble cap tray of a distillation column to give stable operation and even vapour distribution.Answer: None of these Speed of the drum of the rotary vacuum filter normally ranges from __________ rpm.Answer: 0.1 to 2 A stuffing box is used forAnswer: Prevention of fluid leakage around moving parts. Change in volume of metals from absolute zero temperature to their melting points isAnswer: Almost same for all metals. Wohler test is a destructive test to find out the __________ strength of a prepared metal specimen.Answer: Fatigue Needle valves are generally not used forAnswer: Very large diameter pipes. Alloy powder manufactured by the following process have spherical shapes.Answer: Atomisation. Height equivalent to a theoretical plate (HETP) is the height of packing that will give the same separation as one theoretical plate in gas-liquid mass transfer operations like distillation, absorption/stripping and humidification/dehumidification. HETP which is experimentally determined, depends upon theAnswer: All a, b & c. With increase in gas flow rate to fabric surface area ratio (Nm3/hr/m2 fabric surface area), the size & the cost of a bag filterAnswer: Decreases A head comprises of straight flange section, corner torus, section and central dished section. Crown radius and knuckle radius in a head is related respectively to theAnswer: Central dished section and corner torus section. Number of evaporators which can be used in service in a multiple effect evaporation system is limited by theAnswer: Both (a) & (b). Which of the following is used to set the diameter of the distillation column ?Answer: Allowable vapour velocity. Ponchon Savarit method is based on the use of enthalpy concentration diagram, which contains the bubble point curve (saturated liquid curve), dew point curve (saturated vapour curve) and equilibrium tie lines. As compared to McCabe-Thiele's method, this methodAnswer: All 'a', 'b' & 'c'. The optimum size ratio for two mixed reactors in series depends on the kinetics of the reaction and the conversion level. For reaction orders more than one, theAnswer: Smaller reactor should come first. In a shell and tube heat exchanger, tube side __________ of the mass velocity.Answer: Both 'a' & 'b' Which of the following is not a graphical method (but is an analytical method) for the calculation of theoretical number of stages in case of continuous binary distillation?Answer: Sorel-Lewis method. Saddle supports are used for supporting __________ vessels.Answer: Horizontal cylinderical The diameter of a propeller agitator used in agitation tank ranges from __________ percent of the tank diameter and its peripherial speed is normally 300 to 500 metres/minute.Answer: 15 to 30 In packed towers provided with saddle packing, liquid redistributors are positioned at every __________ times column diameter or 6 metres whichever is less.Answer: 5-8 Optimum reflux ratio in a continuous distillation column is determined by theAnswer: Total cost consideration (fixed cost of the column plus the cooling water & steam cost). Cooling water fouling factors vary in the range of 0.001 to 0.003Answer: (BTU/hr.f2°F)−1 Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter )Answer: 0.2 D The maximum liquid gradient over a tray must not exceedAnswer: 0.5" -1.25". An underdesigned steam trap willAnswer: Back up condensate and cause water hammer in steam line. The slope of the feed line in distillation opeartion is given by (where, q = fraction of the feed stream that is liquid.)Answer: -q/(1-q) Speed of industrial paddle agitator ranges from __________ rpm.Answer: 20 to 100 __________ strain is measured using a 'strain rosetter'.Answer: Linear Thin spherical shells subjected to internal pressure, develop __________ stresses.Answer: Radial With increase in the reflux ratio for a fixed production from a continuous binary distillation column, the __________ decreases.Answer: Fixed charges initially