Past Board 2021 Flashcards
Benzene and its derivatives undergo substitution reactions instead of addition reactions because
the integrity of the benzene ring and the stable pi-bonding pattern remains intact
Electrophiles are
electron deficient species
Nucleophiles
electron rich species
SN2 means
one step nucleophilic substitution mechanism involving both alkyl halide and nucleophile
In the decomposition and dissolution of solids during sample preparation, which of the following
is expensive and often the last resort?
Fusion technique
It is important to discard containers that are scratched or abraded on their interior surfaces. The
internal surface area of a container, whether used for sample preparation or storage, may cause
loss of
analyte
Glass container is not suitable for
inorganic trace analyses
Which of the following is a primary standard for use in standardizing bases?
Potassium hydrogen phthalate
A student has got three stock standard solutions of 3 different elements, zinc (Zn) 2000 ppm,
cadmium (Cd) 1500 ppm and lead (Pb) 1000 ppm. A student took 10 mL from each solution and
transfers it to 200 mL volumetric flask then completed to total volume with solvent. What is the
final concentration of each element in the diluted mix solution?
100 ppm Zinc, 75 ppm Cd, 50 ppm Pb
A solution has been prepared by transferring 60 mL from Ortho-phosphoric acid 85 % (v/v)
H3PO4 and diluting it to 1.0 L, what is the concentration of the new solution.
5.10%
The HPLC column type in which molecules are separated according to size.
size exclusion
During ignition for ashing, muffle furnaces that go up to 1100oC are used primarily for this and
________ is needed to contain the sample.
porcelain crucible
A graphical representation of measuring signal as a function of quantity of analyte.
Calibration curve
In AAS method, If the sample concentration is too high to permit accurate analysis in linearity
response range, there are alternatives that may help bring the absorbance into the optimum
working range.
All of the above (sample dilution, using an alternative wavelength having a lower absorptivity, reducing the path length by rotating the burner hand)
A student has to measure out 9.40 mL of a liquid and selects a 100 mL graduated cylinder. To
improve the accuracy of the measurement, it would be most effective to:
measure the liquid using a 10 mL graduated pipette instead
A buffer solution may be a mixture of
all of the above (weak acid and its salt, a weak base and its salt, an excess of a weak acid with a strong base)
What volume is occupied by 4.00 g of carbon dioxide, CO2 (44.0) gas at a pressure of 0.976 atm
and a temperature of 25.00C?
2.28 L
Which statement is true?
A catalyst speeds up both the forward and reverse reaction rates
Law that states the linear relationship between absorbance and concentration of an absorbing
species
Beer-Lambert’s Law
Molecular oxygen is highly soluble in the blood because
the hemoglobin molecule can bind up to four oxygen molecules
A series of reference standards solutions that have known and accurate pH values at different
temperatures used for pH meter calibration.
Buffer Solutions
Type of quality-control sample used to evaluate the effects of sample matrices on the
performance of an analytical method
Matrix Spike
What type of container must be used for acid or alkali wastes?
Polyethylene Drums
When water is heated in a beaker, bubbles of air form on the side of the glass before the water
boils. This shows that
the solubility of gases in water decreases with increasing temperature
The absorbance of different concentrations of potassium permanganate determined through UV-
Vis Spectrophotometer is shown below.
Concentration, ppm Average Absorbance
1.11 0.015
22.2 0.236
44.4 0.512
66.6 0.751
88.8 1.062
The Quality Control Sample for this run gave an average absorbance reading of 0.486. The
theoretical concentration of the QC sample is 44.4 ppm. Calculate for the error of this QC run.
0.0524
Method of passing the sample through a metal or plastic mesh of a uniform cross-sectional area to
separate particles into uniform sizes.
sieving
A solid waste management practice which refers to the controlled decomposition of organic
matter by microorganisms, mainly bacteria and fungi, into a humus-like product.
Composting
In handling acid wastes, what type of protective gloves should be used?
Rubber gloves
Component of error which, in the course of a number of analyses of the same measurand, remains
constant or varies in a predictable way.
Systematic Error
Determine the actual volume contained in a 50.0 mL volumetric flask given the following data:
Mass of water: 50.1227 g Density of water at 25 ̊ C : 0.99707 g/mL
50.27 mL
It is a pure dry solid substance of known chemical composition used in the direct standardization
of solution.
primary standard
Which of the following chemicals may be used to neutralize waste containing caustic soda?
Hydrochloric Acid
Sample preparation technique used prior to instrumental analysis of metals.
acid digestion
It is the closeness of the agreement between the result of a measured value and a true value.
Accuracy
Which of the following are possible routes of exposure of the hazardous effect of waste?
all of the above (Inhalation, Dermal, Ingestion)
According to Revised DAO 04-36, the appropriate waste labels shall include:
All of the above (Volume of Waste, Generator ID Number, Container Material)
Sampling type that eliminates questions of bias in selection
random
Reliability of the results decreases with a decrease in the level or concentration of the:
analyte
Properties of nitric acid making it the preferred acid for digesting samples for the analysis of
metals.
All of the above (acts as a strong acid, as an oxidizing agent, does not form insoluble compounds with metals/nonmetals)
Possible sources of contamination during sample preparation include:
All of the above (Reagents (tracers), Glassware/equipment, Cross-contamination between high- and low-activity samples)
Locating the adulterated portion of the lot for sampling is an example of
selective sampling
The size of the sample taken for analysis depends on the concentration of the
All of the above (analyte, equipment to be used, specific tests)
Requirements of a primary standard.
All of the above (High Purity, 99.9% or better, Stability in air, Absence of hydrate water)
Used for vacuum filtration using filter paper.
Buchner funnel
The substance which does the dissolving and must be greater than 50% of the solution.
solvent
Quantitative chemical analysis of weighing a sample, usually of a separated and dried precipitate.
Gravimetric analysis
A technique for separating mixtures into their components in order to analyze, identify, purify,
and/or quantify the mixture or components.
Chromatography
Chromatography is used to
All of the above (Separate two or more compounds based on their polarities, Separate two or more compounds based on their masses, Separate two or more compounds based on how strongly they interact with other compounds)
In chromatography, ________ is carried out on glass plates or strips of plastic or metal coated
on one side with a thin layer of adsorbent.
Thin Layer Chromatography
A graph showing the detectors response as a function of elution time : band’s shapes, position,
resolution
chromatogram
Under the Bronsted concept of acids and bases, an acid is
a proton donor
Predict the products of the following acid-base reaction: NH3(aq) + HNO3(aq) →
NH4NO3(aq)
Under the Bronsted concept of acids and bases, a base is
a proton acceptor
The solution of impure compound and solvent is concentrated to get ____________
Saturated solution
Which of the following is not a common method used for purification?
Electrolysis
Which of the following is NOT an acid-base conjugate pair?
H2S and OH−
Crystal phases can be interconverted by varying ____________
Temperature
Insoluble impurities from solution during crystallization are removed by ____________
Filtration
Which of the following is not separated through distillation process?
Milk and water
Column chromatography is based on the principle of _______________ (this question appeared
twice)
Differential adsorption
Select the correct statement from the following options.
The greater the polarity of solute, more strongly it will be adsorbed on a polar surface
The elution power of a solvent is determined by ____________
All of the mentioned (Its overall polarity, The polarity of the stationary phase, The nature of the sample components)
The principle on which thin layer chromatography is based is that the ____________
Different compounds are adsorbed on an adsorbent to different degrees
Which type of chromatography is used for the structural analysis?
Paper chromatography
Which of the following is not an application of high performance liquid chromatography?
Elimination of undesirable substances from blood
Which of the following is the application of ion exchange chromatography?
All of the mentioned (The softening of hard water, The demineralisation of water, The separation and determination of anions)
Affinity chromatography is used for the analysis and isolation of ____________
All of the mentioned (Insoluble starch substances, Enzyme tyrosinase, Antibodies bound with a covalently-attached antigen on cellulose column)
The quantitative analysis is done using ____________
Gas chromatography
The temperature at which solid and liquid coexist in equilibrium is called ____________
Freezing point of liquid
The analysis of electromagnetic radiation scattered, absorbed or emitted by the molecule is called
Spectroscopy
The different types of energies associated with a molecule are __________
All of the mentioned (Electronic energy, Vibrational energy, Rotational energy)
Select the correct statement from the following option.
Spectroscopic methods require less time and less amount of sample than classical methods
Which of the following is not in the infrared spectrum?
CH4
The components of the mixture in column chromatography are eluted in order of
increasing polarity and increasing distribution ratio.
Which equipment must be used in the detection of Pb2+ in blood?
AAS
An industrial source of alcohol
Sugar
What is the most common isotope of hydrogen?
Protium
A 22/24 stopper is used in a volumetric flask. Which of the following is true? (Same concept as
this).
The diameter is 22 mm and the height is 24 mm.
In the analysis of a mixture by gas chromatography, which of the following gives the best clue as
to whether the components can be analysed with any degree of accuracy? (Same concept)
Retention times
The determination of the equilibrium constant of a colored species can be done via which
technique?
Spectrophotometry
This type of glass is commonly used for laboratory glassware.
Borosilicate
Why is there a need to separate halogenated waste from non-halogenated waste?
Halogenated waste disposal is more costly
Organic peroxides are dangerous when
All of the above (Heated, Concentrated, Let ether, p-dioxane, THF, among others to vaporize)
This quality system standard is a general requirement for the competence of testing and
calibration laboratories.
ISO/IEC 17025:2005
As P increase while T drops, intermolecular forces are evident, what is applicable?
Ideal gas must be replaced by Van der Waals (?)
In an ideal gas of volume V and temp T. What happens to T when volume is doubled under
constant P?
Doubled
Water is a good solvent for benzoic acid recrystallization.what is the correct preparation of
benzoic solution for recrystallization.
Add small portions of hot water to benzoic acid while stirring until dissolved
If you are going to mass produce vitamin C, which standard should you subscribe in?
GMP or ISO 9000 (or both)
What is the name of RA 6969?
The choices were quite confusing. The correct one should be “Toxic Substances and
Hazardous and Nuclear Wastes”
What type of reactions is hydrogen peroxide to water and oxygen?
Decomposition
What compound is possibly shown in an infrared spectrum which has peaks of 3000 cm-1 and 1650 cm-1
Cyclohexene (?)
According to NFPA, what color refers to flammability
Red
A solution is _______ if more solute can dissolve in it.
unsaturated
Solutions of metals and salts are ______
(NA yet)
Complete name of the acronym MSDS
Material Safety Data Sheet
How many isomers do C5H12 have?
3
Which of the ff are limitations of Lambert-Beer’s Law?
All of the above (Scattering of light due to particles, Fluorescence of sample, Non-monochromatic radiation)
Which of the ff requires the most energy for electronic transition?
Alkanes
Which of the following compounds have the same molecular and empirical formula?
(Choices: Different structures of carboxylic acids )
The process that combines alcohol and carboxylic acid to form an organic compound and water is
called ____
Esterification
Which of the following will cause the mass of the metal block to increase?
None of the above (Putting the block in a freezer, Heating the block, Measuring the mass of the block in Jupiter)
The process in which the relationship of the analytical response and the concentration of the analyte
is established.
Calibration
Which of the following is an acid?
Apple juice
When proteins are broken down by enzymes, the products are:
amino acids
What type of cell converts chemical to electrical energy?
Voltaic or galvanic cells (or both)
Which compound will rapidly decolorize bromine in CHCl3
1-hexene
The gas-solid chromatography is ____________ chromatography as per basic principle involved
Adsorption
Presence of a functional group in a compound can be established by using:
IR Spectroscopy
What is the advantage of using ground glass joints when carrying out a chemical reaction?
All of the above (?), (no purities are introduced in the reactions from corks or rubber stopper, all joints are interchangeable and a good fit is assured, glassware apparatus can easily be assembled)
Which compounds have both cis and trans isomers possible?
Choices: Different organic compounds were given but you can choose which one is an alkene.
- A compound is known to decompose at its boiling point. Which of the following methods can be used to purify this substance
steam distillation
