PPSC Analytical Chemist BS-17 Demo Test

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This test consists of 50 questions with a 30-minute time limit. Ensure a fair attempt, as cheating is strictly prohibited and goes against Islamic teachings. Read each question carefully, select the best answer, and submit before time runs out. Once submitted, answers cannot be changed.

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Created on February 06, 2025 By

Kamran Fateh

Chemical Symbols and Formulae for Elements and Compounds Education Presentation in 0 Flat Graphic Flat Cartoon Style

PPSC Analytical Chemist BS-17 Demo Test

1 / 50

1) Which of the following reagents is best for the selective oxidation of benzyl alcohol to benzaldehyde?

1) a) KMnO₄

2) b) PCC

3) c) LiAlH₄

4) d) NaBH₄

2 / 50

2) The rate constant for a first-order reaction is 0.001 s⁻¹. What is the half-life of the reaction?

1) a) 693 s

2) b) 1000 s

3) c) 500 s

4) d) 10 s

3 / 50

3) Which factor favors an SN1 reaction over an SN2 reaction?

1) a) High steric hindrance

2) b) Strong nucleophile

3) c) Polar aprotic solvent

4) d) Primary alkyl halide

4 / 50

4) The Langmuir adsorption isotherm assumes:

1) a) Multilayer adsorption

2) b) Monolayer adsorption

3) c) No adsorption

4) d) Unlimited adsorption

5 / 50

5) The dead volume in an HPLC system refers to

1) The volume of solvent required to dissolve the sample

2) The volume of mobile phase inside the column

3) The volume of mobile phase in the system before reaching the detector

4) The void space in the stationary phase

6 / 50

6) Which reagent can be used to distinguish between phenol and alcohols?

1) a) Lucas reagent

2) b) Br₂ water

3) c) HCl

4) d) NaOH

7 / 50

7) Karl Fischer titration is used to determine:

1) a) Purity of metals

2) b) Water content in samples

3) c) Alcohol percentage

4) d) Molecular weight

8 / 50

8) The base peak in a mass spectrum represents:

1) a) The most abundant ion

2) b) The heaviest ion

3) c) The molecular ion

4) d) The neutral molecule

9 / 50

9) Which indicator would be most suitable for the titration of a strong acid with a strong base

1) Phenolphthalein (pH range: 8.2 - 10.0)

2) Methyl orange (pH range: 3.1 - 4.4)

3) Bromothymol blue (pH range: 6.0 - 7.6)

4) none

10 / 50

10) If 98 g of H₂SO₄ is completely ionized in 1 L of water, what is the normality of the solution?

1) 0.5 N

2) 0.1 N

3) 1 N

4) 2 N

11 / 50

11) The flame test color for potassium ion is:

1) Green

2) Violet

3) Yellow

4) Blue

12 / 50

12) Which of the following factors does NOT affect the separation of compounds in gas chromatography

1) Column temperature

2) Carrier gas flow rate

3) Sample injection volume

4) Wavelength of UV light

13 / 50

13) Which of the following is used as a reference electrode in potentiometry?

1) (a) Hydrogen electrode

2) (b) Silver-silver chloride electrode

3) (c) Calomel electrode

4) (d) All of the above

14 / 50

14) Carrier gases used in Gas Chromatography (GC) must be:

1) a) Reactive

2) b) Non-reactive and pure

3) c) Heavy and dense

4) d) Condensable

15 / 50

15) The strongest type of intermolecular force present in solid CO₂ (dry ice) is

1) Hydrogen bonding

2) Dipole-dipole interactions

3) London dispersion forces

4) Ionic bonding

16 / 50

16) The working principle of a potentiometer is based on:

1) (a) Ohm’s law

2) (b) Nernst equation

3) (c) Beer-Lambert law

4) (d) Hess’s law

17 / 50

17) Which type of solution will have a concentration below the saturation point?

1) Supersaturated solution

2) Unsaturated solution

3) Saturated solution

4) All

18 / 50

18) EDTA forms a complex with metal ions at:

1) a) Low pH

2) b) High pH

3) c) Neutral conditions

4) d) In presence of chloride ions

19 / 50

19) In High-Performance Liquid Chromatography (HPLC), the most common detector used is:

1) a) UV-Vis Detector

2) b) IR Detector

3) c) X-ray Fluorescence

4) d) Mass Spectrometer

20 / 50

20) In capillary columns used in gas chromatography, the stationary phase is typically

1) A solid adsorbent packed in the column

2) A liquid coated onto the inner wall of the column

3) A gas that interacts with the analytes

4) A metal surface used to catalyze reactions

21 / 50

21) Which is the most abundant protein in the human body?

1) a) Hemoglobin

2) b) Collagen

3) c) Myoglobin

4) d) Keratin

22 / 50

22) Which of the following is an example of a precipitating agent in gravimetric analysis

1) Hydrochloric acid

2) Ammonium sulfate

3) Sodium chloride

4) Ethanol

23 / 50

23) Calculate the root mean square velocity of oxygen gas at 300 K.

1) a) 483 m/s

2) b) 320 m/s

3) c) 615 m/s

4) d) 220 m/s

24 / 50

24) The van Deemter equation in HPLC describes the relationship between

1) Mobile phase flow rate and peak area

2) Column efficiency and particle size

3) Theoretical plates and retention time

4) Mobile phase viscosity and resolution

25 / 50

25) Which of the following factors affect the value of for a reaction?

1) Catalyst

2) Temperature

3) Volume

4) Pressure

26 / 50

26) Which of the following salts will produce an acidic solution when dissolved in water

1) NaCl

2) NH4Cl

3) K₂CO₃

4) Na2SO4

27 / 50

27) The best filter medium for collecting fine precipitates in gravimetric analysis is

1) Filter paper

2) Sintered glass crucible

3) Cotton wool

4) Polyethylene membrane

28 / 50

28) Which of the following graphs correctly represents the pH change when a weak acid is titrated with a strong base

1) A sharp pH rise at the equivalence point

2) A gradual pH rise, followed by a steep increase at the equivalence point

3) A steady pH rise with no significant jumps

4) A sharp pH drop at the equivalence point

29 / 50

29) Which detector in gas chromatography is most sensitive for detecting organic compounds?

1) Flame Ionization Detector (FID)

2) Thermal Conductivity Detector (TCD)

3) Electron Capture Detector (ECD)

4) UV-Vis Spectrophotometer

30 / 50

30) The indicator used in EDTA titration is:

1) a) Phenolphthalein

2) b) Methyl orange

3) c) Eriochrome Black T

4) d) Starch

31 / 50

31) Which molecule has the highest bond energy?

1) a) 𝑁 2

2) b) 𝑂 2

3) c) 𝐻 2

4) d) 𝐶 𝑙 2

32 / 50

32) The ideal precipitate in gravimetric analysis should be:

1) a) Highly soluble

2) b) Easily filterable

3) c) Colloidal

4) d) Hydrated

33 / 50

33) In the redox titration to determine the concentration of I2 with known solution of Na2S2O3, the end point of the titration is

1) blue to pink

2) blue to colorless

3) pink to colorless

4) pink to blue

34 / 50

34)

The solubility product () of at 25°C is . Calculate its solubility in mol/L.

1) a) 1.05×10−5

2) b) 2.3×10−6

3) c) 3.4×10−7

4) d) 8.9×10−4

35 / 50

35) Which of the following is an example of a Lewis acid?

1) BF3

2) H2O

3) NH3

4) OH-

36 / 50

36) Reverse-phase HPLC uses:

1) a) A polar stationary phase

2) b) A non-polar stationary phase and polar mobile phase

3) c) A non-polar mobile phase

4) d) A gas as mobile phase

37 / 50

37) In the equilibrium $C a C O_{3} (s) ⇌ C a O (s) + C O_{2} (g)$ , if the pressure is decreased, what happens to the equilibrium?

1) Shifts to the left

2) Shifts to the right

3) No change, as there are only solids present

4) 𝐾 increases

38 / 50

38) Which of the following is a biodegradable polymer?

1) a) Nylon-6,6

2) b) Polylactic acid (PLA)

3) c) Teflon

4) d) Polyethylene

39 / 50

39) Which solvent favors SN2 reactions?

1) a) Water

2) b) Ethanol

3) c) DMSO

4) d) Acetic acid

40 / 50

40) Highest electron affinity among following is

1) F

2) Cl

3) Br

4) I

41 / 50

41) The half-life of Uranium-238 is 4.5 × 10⁹ years. How much of a 10 g sample will remain after 9 × 10⁹ years?

1) a) 2.5 g

2) b) 5 g

3) c) 1.25 g

4) d) 0.5 g

42 / 50

42) At 700 K, the equilibrium constant for the reaction is 0.50. What is if

1) a) 0.0115

2) b) 0.046

3) c) 0.50

4) d) 1.2

43 / 50

43) The color change in a permanganate redox titration is due to:

1) a) Change in pH

2) b) Formation of MnO₄²⁻

3) c) Reduction of MnO₄⁻ to Mn²⁺

4) d) Precipitation of MnO₂

44 / 50

44) Which of the following does not undergo Friedel-Crafts alkylation?

1) Benzene

2) Toluene

3) Aniline

4) Chlorobenzene

45 / 50

45) In Atomic Absorption Spectroscopy (AAS), the source of radiation is:

1) a) Tungsten lamp

2) b) Hollow cathode lamp

3) c) Monochromator

4) d) Laser

46 / 50

46) Which reaction order has a constant half-life?

1) a) First-order

2) b) Second-order

3) c) Zero-order

4) d) Third-order

47 / 50

47) In the Mohr,s method of precipitation titration, indicator used is

1) floroscein

2) ferric alum

3) 5% K2CrO4

4) none of these

48 / 50

48) The Fajan’s rule predicts the extent of

1) Covalent character in an ionic bond

2) Ionic character in a covalent bond

3) Metallic character in an element

4) Hydrogen bonding strength

49 / 50

49) Greenhouse gases include:

1) a) CO2 , 𝐶 𝐻4 , 𝑁2O

2) b) 𝑂2 , 𝑁2

3) c) 𝐴 𝑟, He

4) d) 𝑁𝐻3, 𝐻𝐶 𝑙

50 / 50

50) Which of the following does not give a positive iodoform test?

1) a) Acetone

2) b) Acetaldehyde

3) c) 2-Butanone

4) d) Formaldehyde

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The average score is 54%