Pakistan's MCQ Practice Library for Competitive Exams

A. A horizontal line on the humidity chart indicates the temperature changes at constant molal

B. idity

C. When water is cooled from 80 to 70C by exposure to the air with a wet bulb temperature of

D. C, then both the approach & the range would be 10C

E. For unsaturated air-water vapor mixture at atmospheric conditions, the wet bulb temperature

F. p; adiabatic cooling lines are the same

A. Polythene is a copolymer, while SBR is a homopolymer

B. Protein is a natural polymer

D. Polystyrene is a thermoplastic polymer

B. One important copolymer of styrene is SBR, which is widely used in the manufacture of

C. For the manufacture of styrene, the major raw materials are benzene and ethylene

D. Manufacture of phenol by chloroben-zene-eaustic process involves. The chlorination of benzene, causticisation and hydrolysis

E. omobile tyres

A. Momentum transfer in laminar flow results from velocity gradient

B. A fluid in equilibrium is not free from shear stress

C. The viscosity of a non-Newtonian fluid is a function of temperature only

A. Characterisation factor of paraffinic crude oil is more than 12

B. Pensky-Marten apparatus is used for determining flash points above 50C

C. Abel apparatus is used for determining flash points below 50C

A. The ratio of immediately available cash to the total current liabilities is known as the cash

B. io

C. Gross revenue is that total amount of capital received as a result of the sale of goods or service

E. ws the relationship among total income, costs & profit over the time interval

F. Consolidated income statement based on a given time period indicates surplus capital and

A. estment

B. Annual depreciation rate of buildings in a chemical plant is about 3% of its initial cost

C. Insurance rates on annual basis in a chemical plant may be about 1% of the fixed capital

D. ut 10% of the fixed capital investment

E. lisation (NSR)</strong>

F. The annual depreciation rate for machinery and equipments in a chemical process plant is

A. Value of Stefan-Boltzmann constant is 4.876 10-8 KCal/m2.hr.K4

B. Absorptivity of a body approaches unity in case of diffuse reflection

D. Absorptivity of a perfectly black body is unity

A. Phase change in case of a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature

B. The controlling resistance in case of heating of air by condensing steam is in the air fil

C. The log mean temperature difference (LMTD) for counter flow and parallel flow can be theoretically same when any one of the fluids (hot or cold fluid) passes through the heat exchanger at constant temperature

D. rply, when a temperature cross occurs</strong>

A. Both annealing and normalising release the internal stresses of the material besides improving

B. mechanical properties

C. Low carbon steel does not respond to the heat treatment for hardening of the material, hence it

D. subjected to case hardening or surface hardening processes like cyaniding, carburising,

E. riding etc., which produces high carbon outer layers resulting in increase of surface

F. dness

A. Theoretical flame temperature is the temperature attained by the products of combustion, when the fuel is burned without loss or gain of heat

B. Burning the fuel with theoretically required amount of pure oxygen results in attainment of maximum adiabatic flame temperature

D. Adiabatic flame temperatures of actual combustions are always less than the maximum values

A. versal jaw crushers

B. Operating principles of Dodge and Blake jaw crushers are combined in the working of

D. er one

E. uction equipments employ

F. There are only four methods namely compression, impact, attrition and cutting, which the size

B. Hammer crushers operate by impact action

C. Standard screens have circular opening

D. With increase in mesh number of screens, their diameter in microns decreases

A. Paramagnetic susceptibility of gases permits the measurement of their concentration

C. O2, NO and NO2 exhibit paramagnetic properties as a result of unpaired electrons

D. Paramagnetic susceptibility of gases decreases with temperature

A. Most of the hydrocarbons are non-polar

C. ionise

D. Generally, non-polar compounds are chemically inactive, conduct electricity poorly and do

E. Molecules with symmetrical arrangements (e.g. CH4 or CCl4) are non-polar

B. In nylon-6, the number 6 represents the total number of carbon atoms in the ring

C. Ethanolamines are produced by using ammonia and ethylene oxide as raw material

D. Catalytic hydrogenation of carbon monoxide produces methyl alcohol

A. In case of a packed tower, the operating velocity is about half of the flooding velocity,

B. idity</strong>

C. Change in barometric pressure does not affect the relative humidity

D. Elution means the desorption of the adsorbed solute by a solvent

F. erally

A. Refractories used for lining electrical furnaces should ordinarily have very low electrical

B. Electrical conductivity of porous refractory material is low

C. ctrical insulators

D. naces</strong>

E. ductivity

A. rogen is 4

C. For a two phase system in equilibrium made up of four non-reacting chemical species, the

D. orisation and sublimation</strong>

E. ber of degrees of freedom is 4

F. Minimum number of degree of freedom of a system is zero

A. Addition of methane to the furnace atmosphere reduces decarburising by hydrogen

C. Active nitrogen (formed by cracking ammonia at the metal surface) cause nitride formation

D. h increase in surface hardness

E. burise the surface of steel at annealing temperatures

F. Nitrogen in presence of steam decor-burises high carbon steel, whereas hydrocarbon gases

A. ther

B. Elutriation process refers to when the soluble material is largely concentrated on the surface of

D. insoluble solid and is simply washed off by the solvent

E. Cellulose acetate membranes are used in dialysis process

F. Cascade means a group of stages interconnected so that various streams flow from one to

A. Tin exists in two allotropic forms

B. The predominant use of tin is in the form of coating for steel & copper alloys

C. Tin can be severely cold worked without the necessity of annealing due to its low recrystallisation temperature

A. Increase in depth of the liquid about the slots increases the plate efficiency, particularly if the liquid depth is < 1"

B. Plate efficiency increases with increase in superficial vapour velocity till entrainment limit

D. Too small a plate spacing can cause a low efficiency, if the vapour velocity is greater than the allowable value

A. For all the cylindrical process vessels operating above atmospheric pressure, formed heads are used for closing the vessel

B. Fouling factor of river water is less than that of sea water

C. Risers provided in bubble cap trays in the distillation column facilitate the flow of both liquid and vapor

A. Adiabatic flame temperatures of actual combustions are always less than the maximum values

B. Theoretical flame temperature is the temperature attained by the products of combustion, when the fuel is burned without loss or gain of heat

D. Burning the fuel with theoretically required amount of pure oxygen results in attainment of maximum adiabatic flame temperature

A. C.V. of natural gas is about 10000 KCal/Nm3

C. C.V. of LPG is about 26000 kcal/Nm3 (11500 kcal/kg)

D. Main constituents of LPG are propane and butane

A. Cold SBR is superior as compared to hot SBR

C. Polymerisation temperature can modify the properties of SBR

D. Production of cold SBR employs lower pressure as compared to that of hot SBR

A. Addition polymers are generally formed by chain growth polymerisation

C. Bakelite is formed by step growth polymerisation

D. Condensation polymers are generally formed by step growth polymerisation

A. Hydrochloric acid-water

C. Benzene-toluene

D. All A., B. and C.

A. Aluminium sulphate

C. Hydrated lime

D. Ferrous sulphate

A. ?p/? = 4f (L/D) (V2/2gc)

C. cDp)

D. ?p/L = 150 [(1 ?)/?3]. (?.V0

E. 2cD)

F. ?p/L = 1.75 [(1 ?)/?3]. (?V0

A. Water with pH value less than 7, is acidic

B. Sodium sulphate or sodium carbonate do not cause hardness in water

C. Aeration of water is effective in CO2 removal

B. Surface tension

C. Refractive index

D. Specific heat

B. Chemical equilibrium is a static state

C. A photochemical reaction is catalysed by light

D. A chemical reaction occurs when the energy of the reacting molecule is less than the activation energy of the reaction

A. Random packing a packed tower offers the advantage of lower pressure drop and higher throughput of fluids as compared to regular/stacked packing

B. Draining of residual liquid on tray during shut down of distillation column is facilitated by weep holes

C. It is preferred to use a vertical condenser for condensation of vapor from a distillation column without sub-cooling

A. None of these

B. Throughout the converging portion of the tube, the density increases in the downstream

D. ection

E. The value of Mach number is always unity at the throat

A. Reynolds number of condensing liquid is based on its mass flow rate

C. Filmwise condensation gives a lower heat transfer rate than the dropwise condensation

D. ce on it

E. If a condensing liquid does not wet the surface dropwise, even then condensation will take

A. een, is called Work index

C. Energy required in kwh per ton of product, such that 80% of it passes through a 200 mesh

D. Plastic chips are called non-cohesive solids

E. Communition is a generic term for size enlargement operation

A. COD is related to BOD of a given waste in water but the relationship varies for different

B. hromate in cone, sulphuric acid solution at boiling temperature for specified time

C. tes. Typically COD of potable water may be 1-2 mg/litre

D. Chemical oxygen demand (COD) is a measure of chemically oxidisable organic matter present

E. water

F. COD is determined by oxidising the organic matter present in water with potassium

A. Dialysis process is used for the production of fresh water from brine

C. Electrodialysis is used for the refining/purification of petrol

D. Both B. and C.

B. The pressure drop through the packed towers is generally more than the pressure drop through plate towers designed for same duty

C. None of these

D. When highly corrosive fluids are to be handled, the plate towers prove to be cheaper and easier to construct than packed tower

A. Law of mass action was suggested by Le-Chatelier

B. A catalyst changes the equilibrium point

C. rgy

D. The difference between the energy of reactants and that of the products is the activation

A. Heat added to or given up by a substance at constant temperature is called the sensible heat

B. A mixture of vapor gas is called saturated, if the equilibrium vapor pressure of the liquid is

C. e than the partial pressure of the vapor at the same temperature

D. A substance existing above its critical temperature is called a saturated vapor

A. 1 calorie = 252 BTU

C. 1 BTU =453.6 calories

D. 1 calorie = 453.6 BTU

B. Specific gravity

C. Flashpoint

D. Viscosity

A. Edward A. Shills

B. G.A. Almond

C. Karl Marx

D. Max Weber

A. visual symbols

C. verbal symbols

D. spoken (not mental) verbal symbols

A. viscosity only

B. unit weight only

D. none of the above

A. All the above

B. Granulation

D. Tillage

B. In insecticides manufacture

C. For making nylon-6

D. In making PVC