Pakistan's MCQ Practice Library for Competitive Exams

A. Rate of digestion of sludge is more at higher temperature

B. Mesophilic organisms digest the sludge if the temperature is between 25 and 40C

C. Thermophilic organisms digest the sludge if the temperature ranges from 40 to 60C

A. cornish is fire tube and lancashire is water tube

B. cornish is water tube and lancashire is fire tube

C. cornish has two fire tubes and lancashire has one

E. both have two fire tubes

A. free float > total float

B. free float = total float

D. independent float > free float

E. independent float = total float

A. none of the above

B. all of the above

D. gas turbine uses low air-fuel ratio to economise on fuel

E. gas turbine uses low air-fuel ratio to develop the high thrust required

A. For petrol and large gas engines, quantity governingds preferred

B. In quantity governing, air fuel ratio is almost constant and quantity of charge is changed depending on load

C. In hit and miss governing, fuel supply is completely cut off during one or more number of cycles

E. For close regulation of speed, combination of both quality and quantity governing is used

A. Psilophyton

C. Rhynia

D. Cooksonia

A. 1 lb/hr.ft2 = 4.8823 kg/hr.m2

C. 1 lb/hr.ft3.atm. = 4.8182 kg/hr.m2.bar

D. 1 kg/hr.m2.atm= 0.98687 kg/hr. m .bar

A. 1 kcal = 3.968 BTU = 0.00116 kWh = 0.00156 hp

B. 1 ton of TNT (tri-nitro-toluene) = 4.2 GJ (1G = 109)

C. 1 ft.lbf= 0.3238 calorie = 0.1383 kg.m = 1.356 J = 1.356 N.m

A. 1 Pascal second = 10 poise

C. 1 ppm = 1 ml/m3 = 1 mg/kg

D. 1 kgf= 9.8 Newton

A. s compared to that for strong acids and bases

B. a</strong>

C. solution of the anhydrous substance and its heat of hydration

D. ure & amount of the solute & the solvent, on the temperature & on the initial & final

E. centrations of the solution

F. The accompanying enthalpy change, when a solute is dissolved in solvent, depends upon the

A. The net change in entropy in any reversible cycle is always zero

B. The entropy of the system as a whole in an irreversible process increases

C. The entropy of the universe tends to a maximum

A. System (of partially miscible liquid pairs), in which the mutual solubility increases with rise

B. temperature, are said to possess an upper consolute temperature

C. Systems, in which the mutual solubility increases with decrease in temperature, are said to

D. sess lower consolute temperature

E. Nicotine-water system shows both an upper as well as a lower consolute temperature,

F. lying that they are partially miscible between these two limiting temperatures

A. The chemical formula of oleum is H2S2O7, which is formed by saturating sulphuric acid with

B. Vitriol oil is nothing but technical sulphuric acid

C. phur trioxide

D. Conversion of SO2 to SO3 in Monsanto-4 pass converter is about 98%

A. Gypsum is added to Portland cement to lengthen its setting time

C. Dry process is used for the manufacture of cement, when the raw material is blast furnace slag

D. Portland cement is made employing wet process

A. The tensile strength of a brittle material is less than its compressive strength

B. The compressive strength of a ductile material is less than its tensile strength

D. In a thick cylindrical shell, the hoop stress is maximum at the inner radius

A. Split ring type and pull through type floating heads are two commonly used floating heads is

B. t exchangers

D. Pressure drop on the shell side of a heat exchanger depends upon tube pitch also

E. In a horizontal tube evaporator, surface blanketing by air is avoided

B. The integral method of analysing kinetic data is used when the data is scattered

C. The ratio of volumes of plug flow reactor to that of mixed reactor is always less than one for identical feed composition, flow rate, conversion and for all positive reaction orders

D. The differential method of analysing kinetic data requires more accurate or larger amounts of data

A. Volume occupied by 9.034 x 1023 atoms of oxygen in ozone (O3) at NTP will be 11200 c.c

B. perature, then the fraction of total pressure exerted by the oxygen is 1/2

C. When equal weights of oxygen and methane are mixed in an empty reactor at room

E. Ten times dilution of a normal solution (N) reduces its normality to N/10

A. Presence of inerts affects the equilibrium conversion of

B. Use of different catalysts in a reversible catalytic chemical reaction does not change the

C. Alumina is added as a promoter to iron catalyst in ammonia synthesis reaction

D. ilibrium composition

A. Clausius-Clapeyron equation relates the latent heat of vaporisation to the slope of the vapor pressure curve

C. Clapeyron equation is given by dP/dT = (?/T) (VG VL); where, P = vapor pressure, T = absolute temperature, ? = latent heat of vaporisation, VG and VL = volumes of gas and liquid respectively

D. At the boiling point of liquid at the prevailing total pressure, saturated absolute humidity is infinite

A. There is no transfer lag for a single first order system

B. Transfer lag is a characteristic of all higher order systems (other than first order systems)

C. Stirred tank with a water jacket exemplifies an interacting system

A. Most of the enzyme catalysed reactions involve at least two substrates

B. Catalytic activity of enzyme catalysed reactions which is affected by temperature, pH value &

C. rmodynamic properties of substrates & products

D. mical agents, is maximum at a temperature of about 45C

F. Equilibrium concentrations in enzyme catalysed reactions can be calculated by using the

A. Metal/alloys having hexagonal crystal lattice structure are less malleable than those having

B. ic crystal lattice structure

C. Metal/alloys having body centred cubic (bcc) crystal lattice structure is stronger & less ductile

D. n those having face centred cubic (fcc) crystal lattice structure

F. Both ferritic & austenitic stainless steel has a face centred cubic (fcc) crystal structure

A. Pure rubber is as useless as pure gold as a material of construction

C. Copper has poor weldability

D. Reinforced plastics are made from both thermoplastic as well as thermosetting plastics

A. ghness & Reynolds number

C. Greater is the kinematic viscosity of the liquid, greater is the thickness of the boundary layer

D. Fanning friction factor in case of turbulent flow of liquids in pipe depends upon relative

E. Blowers develop a maximum pressure of 2 atmospheres

A. Graphite refractories are also called plumbago refractories

B. Calcined magnesite is also called dead burnt magnesite

D. Insulating refractories used in place of regular refractory bricks are usually called light weight

E. ractories, and they have similar composition as heavy bricks

A. A dust catcher is simply an enlargement in a pipeline which permits the solids to settle down

B. Wear and tear in wet crushing is more than that in dry crushing of materials

C. to reduction in velocity of the dust laden gas

E. Recycled coarse material to the grinder by a classifier is termed as circulating load

A. For reducing spalling tendency, the refractory should be well fired and its porosity should be more

B. Refractoriness under load (RUL) of a refractory is always less than its refractoriness

C. The electrical resistivity of refractories drops rapidly with rise in temperature

A. The evaporation of aqueous solution of glucose causes its molarity to increase

B. Both the freezing point as well as boiling point of sea water is more than that of distilled water

C. The solution containing equal masses of two liquids X and Y has the same mole fraction of

D. 216;X and Y

A. Heat capacity of a diatomic gas is higher than that of a monatomic gas

C. Total number of molecules contained in 22.4 litres of hydrogen at NTP is 6.023 x 1023

D. The binary mixture of a particular composition in both vapor and liquid state is known as an azeotropic mixture

B. The phosphorous nutrient makes the plant stem stronger and increases its branches

C. A straight fertiliser contains only one nutrient

D. Calcium cyanamide is used as weed killer in onion fields

A. Pure rubber is as useless as pure gold as a material of construction

C. Copper has poor weldability

D. Reinforced plastics are made from both thermoplastic as well as thermosetting plastics

B. Troutons ratio of non-polar liquids is calculated using Kistyakowsky equation

C. Thermal efficiency of a Carnot engine is always less than 1

D. None of these

B. Contacting cold vapor-gas mixture with hot liquid exemplifies humidification process

C. Diffusion co-efficient and mass transfer co-efficient are not same in any mass transfer

D. Contacting cold liquid with warm vapor-gas mixture exemplifies dehumidification process

E. ration

A. ponents</strong>

B. The solubility of a particular gas in ideal solution in any solvent is always the same

C. The operating line always lies above the equilibrium solubility curve in case of a single

D. ponent stripper

E. The operating line always lies below the equilibrium solubility curve in case of a single

B. None of these

C. t particles from flue gases at very high temperature</strong>

D. A slight haze at the top of chimney indicates good combustion in the furnace

E. micronic dust particles present in flue gas

F. Electrostatic precipitator is the most efficient dust collection equipment for removal of

A. ?-particle emission from a radioactive element makes it electrically negative

C. The disintegration constant of a radioactive isotope is independent of pressure, temperature or concentration

D. ?-particle emission from a radioactive element makes it electrically positive

A. Azoic dyes are mostly applied on cotton fabrics

C. Mordant dyes are applied mainly to wools

D. Basic dyes (e.g. amino derivatives) are applied mostly to paper

A. The viscosity of a liquid increases with decrease in temperature

B. The viscosity of gas increases with increase in temperature

C. The eddy viscosity is a function of the type of turbulence involved

A. Multigrade lubricating oils have high viscosity index

B. Naphthenic oil has very low viscosity index

C. Paraffinic oil has very high viscosity index

A. The shear stress at any given cross-section of a pipe for steady flow (either laminar or turbulent) varies linearly as the radial distance

B. The form drag is dependent upon the occurrence of a wake

D. Existence of the boundary layer in fluid flow is because of viscosity of the fluid.

B. Organic pigments are used as colouring materials in the soap manufacture

C. Both laundry as well as toilet soaps are manufactured by hot process

D. Colourless rosin is used in the manufacture of laundry soaps

A. Steam is fed to the shell, whereas the liquor is filled inside the tube

B. Tube dia is 3-6 cms, while tube length in 3-6 metres

D. Liquor level is maintained at 1/3rd to 1/2 of the height of the tube

A. Its usual dimensions are: tube dia = 2-3 cms; evaporator body dia = 1-4 metres and evaporator

B. ght = 2.5-4 metres

C. It is suitable for process, in which the final product is a liquor instead of solid

D. It is unsuitable for concentrating those liquids, which form a scale or deposit salt

A. Increases with the increasing flake size keeping the flake thickness constant

B. Decreases with decrease of thickness of the flakes

C. Increases considerably with the rise of temperature

A. Increases with the increasing flake size keeping the flake thickness constant

B. Increases considerably with the rise of temperature

D. Decreases with decrease of thickness of the flakes

A. e ultra-violet rays) to pass through the glass and heat up the soil thereby warming up plants

B. the glass of the green house

C. Green house (made of glass) allows visible sunlight (i.e., short wavelength solar radiation

D. ide it

E. acts like the glass of green house thereby warming up the earths surface

F. Green house effect in earths atmosphere is due to increasing CO2 level in atmosphere, where

A. Decreases with increase in hardness, in general

B. Decreases with increase in strain hardening tendencies

D. Depend on the composition, microstructure and physical & mechanical properties

A. The viscous fluid should be routed through the shell side

B. The corrosive and fouling fluid should be preferably routed through the tubes

D. Lower flow rate fluid should be routed through the shell side

A. In differential (simple) distillation, the vapour is removed as soon as it is formed without appreciable condensation

B. Distillation under vacuum is a substitute for steam distillation

D. In flash (equilibrium) distillation, a definite fraction of liquid is vaporised in such a way that the evolved vapour & residual liquids are in equilibrium with each other