ORGANIC AND LABORATORY CHEMISTRY
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Questions and Answers

Solvent extraction is more effective when the extraction is repeated with

  • extra solvent
  • large solvent
  • small solvent (correct)
  • no solvent

    • The insoluble impurities during recrystallization are removed by

  • hot gravity filtration (correct)
  • vacuum filtration
  • cooling
  • drying

    • Calculate the percent yield if 0.85 g of aspirin is produced in the reaction of 1.00 g of salicylic acid with excess acetic anhydride. (no. 43 reviewer)

  • 65% (correct)
  • 77%
  • 85%
  • 91%

    • During recrystallization, 0.85 g of crude aspirin was dissolved in a suitable solvent and after filtration and drying, 0.68 g of crystals were recovered. Calculate the % recovery.

    <p>80%</p> Signup and view all the answers

    Which of the following is NOT separated using distillation?

    <p>milk and water</p> Signup and view all the answers

    Steam baths are often used to heat volatile, non-aqueous, flammable solvents because of the following EXCEPT

    <p>Overheating is possible</p> Signup and view all the answers

    The beads in a fractional column are for

    <p>vapors to condense</p> Signup and view all the answers

    Fractional distillation is a process of separation of which of the following?

    <p>two miscible liquids</p> Signup and view all the answers

    What is the advantage of steam distillation?

    <p>Reduces decomposition of temperature-sensitive compounds</p> Signup and view all the answers

    Which of the following is NOT true about steam distillation?

    <p>very short extraction times</p> Signup and view all the answers

    Which of the following is the correct way to determine the boiling point of an unknown compound?

    <p>Boiling a compound and placing the thermometer in the refluxing vapor.</p> Signup and view all the answers

    The principle of TLC is that

    <p>Different compounds are adsorbed on an adsorbent to different degrees.</p> Signup and view all the answers

    Which of the following statements about visualization during TLC is TRUE?

    <p>All of the above.</p> Signup and view all the answers

    Amino acids can be detected by spraying the stationary phase with ninhydrin solution. This can be done in

    <p>paper chromatography</p> Signup and view all the answers

    A substance is analyzed by paper chromatography, giving the chromatogram shown. What is the Rf value of the substance represented by the spot at 8.0 cm?

    <p>0.75</p> Signup and view all the answers

    Karl Fischer titration, which determines trace amounts of water in a sample, uses which electrochemical method?

    <p>Coulometry</p> Signup and view all the answers

    Which of the following is NOT a common method used for purification?

    <p>Electrolysis</p> Signup and view all the answers

    Method of passing the sample through a metal or plastic mesh of a uniform cross-sectional area to separate particles into uniform sizes.

    <p>sieving</p> Signup and view all the answers

    In the decomposition and dissolution of solids during sample preparation, which of the following is expensive and often the last resort?

    <p>fusion technique</p> Signup and view all the answers

    Sample preparation technique used prior to instrumental analysis of metals.

    <p>acid digestion</p> Signup and view all the answers

    In handling acid wastes, what type of protective gloves should be used?

    <p>rubber gloves</p> Signup and view all the answers

    The following are the minimum requirements for hazardous waste storage facilities EXCEPT

    <p>Enclosed and should not be ventilated.</p> Signup and view all the answers

    It is a hazardous waste characteristic which applies to wastes that have the potential to contaminate groundwater if improperly disposed of. These materials are regulated as hazardous waste due to their potential to leach out specific toxic substances in a landfill.

    <p>toxicity</p> Signup and view all the answers

    What should you do when a waste container has a minor leak?

    <p>Transfer to another container</p> Signup and view all the answers

    According to NFPA, what color refers to flammability?

    <p>red</p> Signup and view all the answers

    Which of the following can be disposed down the drain?

    <p>None of the above</p> Signup and view all the answers

    The following are good sampling practices EXCEPT

    <p>Collect the sample in a container made of material that will chemically react with the sample.</p> Signup and view all the answers

    Organic peroxides are dangerous when

    <p>All of the above</p> Signup and view all the answers

    When using a fume hood, all of the following must be done EXCEPT

    <p>Using the hood as a storage area for volatile chemicals when appropriate storage cabinet is not available.</p> Signup and view all the answers

    According to the GHS, which of the following is NOT under the pictogram “Gas Cylinder”?

    <p>explosive gas</p> Signup and view all the answers

    A technical document, which is GHS compliant, that contains all the information related to the health hazard, storage, precautionary measures, emergency procedures, etc. when handling chemicals.

    <p>Safety Data Sheet</p> Signup and view all the answers

    Chromatography is used to

    <p>All of the above</p> Signup and view all the answers

    Which type of chromatography is used for structural analysis?

    <p>Paper chromatography</p> Signup and view all the answers

    Which of the following can be separated using column chromatography?

    <p>chlorophylls and carotenoids</p> Signup and view all the answers

    Affinity chromatography is used for the analysis and isolation of

    <p>all of the mentioned</p> Signup and view all the answers

    Which of the following is useful for the separation of low molecular weight gases?

    <p>Gas-solid chromatography</p> Signup and view all the answers

    The analysis and separation of industrial products like soap and synthetic detergents is done using

    <p>Gas chromatography</p> Signup and view all the answers

    Ion exchange particles carry fixed positive or negative charges. A sulfonic acid type resin has SO3–H+ groups were H+ can be exchanged for

    <p>cations</p> Signup and view all the answers

    A graph showing the detector’s response as a function of elution time, band’s shapes, position, and resolution.

    <p>chromatogram</p> Signup and view all the answers

    A technique for separating mixtures into their components in order to analyze, identify, purify, and/or quantify the mixture or components.

    <p>chromatography</p> Signup and view all the answers

    Which of the following is NOT an application of high performance liquid chromatography?

    <p>Elimination of undesirable substances from blood</p> Signup and view all the answers

    Quantitative analysis can be done using

    <p>Gas chromatography</p> Signup and view all the answers

    Which of the following statements about spectroscopic methods is correct?

    <p>Spectroscopic methods require less time and less amount of sample than classical methods.</p> Signup and view all the answers

    Which of the following demonstrates proper drying of cuvette?

    <p>blot on absorbing towel or tissue paper and allow to air dry</p> Signup and view all the answers

    Which of the following is NOT a limitation of Beer-Lambert’s law?

    <p>Beer-Lambert’s law does not form the quantitative basis for all types of absorption spectroscopy.</p> Signup and view all the answers

    A graphical representation of measuring signal as a function of quantity of analyte.

    <p>calibration curve</p> Signup and view all the answers

    Which of the following compounds would show the longest wavelength max in its UV spectrum? (see mock exam no. 57)

    <p>III</p> Signup and view all the answers

    Which species of the following is used to bombard with the sample for which mass spectroscopy has been performed?

    <p>electrons</p> Signup and view all the answers

    Which of the following molecules will NOT show an infrared spectrum?

    <p>CO2</p> Signup and view all the answers

    In the past, IR spectra had to be acquired one wavelength at a time, which took a long time. Today spectra can be acquired faster due to the

    <p>Fourier Transfer algorithm which allows to scan all frequencies at once</p> Signup and view all the answers

    What compound is possibly shown in an infrared spectrum with peaks of 3000 and 1650 cm-1?

    <p>cyclohexene</p> Signup and view all the answers

    NMR spectroscopy indicates the chemical nature of the __________ and spatial positions of __________.

    <p>Nuclei, neighboring nuclei</p> Signup and view all the answers

    In which species are all the carbon atoms sp2 hybridized?

    <p>C2H4</p> Signup and view all the answers

    What is the hybridization of the carbon atom in a carboxyl group?

    <p>sp²</p> Signup and view all the answers

    In which species Is the carbon-nitrogen bond the shortest? (SEE MOCK EXAM NO. 65)

    <p>IV</p> Signup and view all the answers

    How many different compounds have the formula C5H12?

    <p>3</p> Signup and view all the answers

    How many different alcohols (not including stereoisomers) have the molecular formula C₄H₁₀O?

    <p>4</p> Signup and view all the answers

    For which compound are the empirical and molecular formulas the same?

    <p>C6H5COOH</p> Signup and view all the answers

    Which is the correct molecular formula of the following molecule? (SEE MOCK NO.69)

    <p>II</p> Signup and view all the answers

    Which is the correct IUPAC name of the following compound? (SEE MOCK NO.71)

    <p>5-bromo-3-ethylhept-3-ene</p> Signup and view all the answers

    Identify the incorrect statement regarding cycloalkanes.

    <p>They have tetrahedral bond angles</p> Signup and view all the answers

    Which has the highest boiling point? (SEE MOCK NO.73)

    <p>III</p> Signup and view all the answers

    Which of the following reactions will consume the most oxygen?

    <p>All the given compounds win consume the same amount of oxygen.</p> Signup and view all the answers

    Which set of reagents can perform the following reaction? (SEE MOCK NO. 75)

    <p>O3, Zn/CH3COOH</p> Signup and view all the answers

    Which of the following is NOT a reagent for hydrogenation of an alkyne?

    <p>BH3/H2O2, NaOH</p> Signup and view all the answers

    When ethyne is subjected to ozonolysis, what is the end product?

    <p>formic acid</p> Signup and view all the answers

    Which of the compounds below will react readily with chlorine by addition? I. C2H2 (ethyne) II. C2H4 (ethene) III. C6H6 (benzene)

    <p>I and II only</p> Signup and view all the answers

    What is the order of reactivity of the following compounds in EAS? I. benzene II. toluene III. phenol IV. benzoic acid

    <p>IV &lt; I &lt; II &lt; III</p> Signup and view all the answers

    What are the reagents needed in bromination of benzene via EAS?

    <p>Bromine and FeBr3</p> Signup and view all the answers

    Which of the following is NOT true for SN1 reactions?

    <p>They occur through a single step concerted reaction.</p> Signup and view all the answers

    A low concentration of nucleophile favors

    <p>Neither SN1 nor SN2</p> Signup and view all the answers

    Which statement(s) about substitution reactions are correct? I. The reaction between NaOH and 1-chloropentane predominantly follows an SN2 mechanism II. The reaction between NaOH and 2-chloro-2-methylbutane predominantly follows an SN2 mechanism. III. The reaction between NaOH with 1-chloropentane occurs at a slower rate than with 1-bromopentane

    <p>I and III</p> Signup and view all the answers

    Which of the following alcohols would be most soluble in water?

    <p>Propanol</p> Signup and view all the answers

    Which compound is a tertiary alcohol? (SEE MOCK N0. 85)

    <p>I</p> Signup and view all the answers

    The gentle oxidation of ethanol produces which of the following product?

    <p>II. ethanoic acid</p> Signup and view all the answers

    The major reason that phenol is a better Bronsted acid than cyclohexanol is

    <p>the pi electrons stabilize the phenoxide ion by resonance.</p> Signup and view all the answers

    Which compound is NOT an ether? (SEE MOCK NO.88)

    <p>II</p> Signup and view all the answers

    Which compound is NOT an aldehyde? (SEE MOCK NO. 89)

    <p>III</p> Signup and view all the answers

    What is the IUPAC name for CH₃CH₂CH₂CH₂CHO?

    <p>pentanal</p> Signup and view all the answers

    Which of following Is produced when hydrogen is reacted with 2-butanone? (NO ANSWER)

    <p>tertiary</p> Signup and view all the answers

    Which of these compounds contain a carboxy group?

    <p>propanoic acid</p> Signup and view all the answers

    The smell of rancid butter is due to the presence of butyric (butanoic) acid. What is the formula for this compound?

    <p>C4H8O2</p> Signup and view all the answers

    Which family of compounds is most frequently used as flavoring agents?

    <p>esters</p> Signup and view all the answers

    Calculate the percent yield when 0.5 mol of acetic acid reacts with 1 mol of alcohol produces 0.25 mol of ethyl acetate.

    <p>50%</p> Signup and view all the answers

    Which compound is a tertiary amine? (SEE MOCK N0. 96)

    <p>IV</p> Signup and view all the answers

    Which of the following compounds are basic?

    <p>amines</p> Signup and view all the answers

    The most notable difference between a saturated and an unsaturated fat containing the same number of carbon atoms is that the saturated fat

    <p>melts at a higher temperature.</p> Signup and view all the answers

    When proteins are broken down, they are converted to

    <p>amino acids</p> Signup and view all the answers

    Molecular oxygen is highly soluble in the blood because

    <p>the hemoglobin molecule can bind up to four oxygen molecules.</p> Signup and view all the answers

    Water is soluble solvent for the recrystallization of benzoic acid. How should be addition of the solvent?

    <p>Add small portions of hot water to benzoic acid while stirring until benzoic acid dissolves.</p> Signup and view all the answers

    The organic liquid in steam distillation vaporizes at

    <p>A lower temperature than its boiling point</p> Signup and view all the answers

    Column chromatography is based on the principle of

    <p>Differential adsorption</p> Signup and view all the answers

    The components of the mixture in the column chromatography are eluted in order of

    <p>increasing polarity and increasing distribution ratio</p> Signup and view all the answers

    A simple fractional tube is packed with which of the following?

    <p>Glass beads</p> Signup and view all the answers

    The chromaplate or thin layer chromatography plate is made up of

    <p>Glass</p> Signup and view all the answers

    Retardation factor is the ratio of

    <p>Distance moved by substance from baseline to distance moved by the solvent from baseline</p> Signup and view all the answers

    Which of the following is FALSE regarding galvanic cells?

    <p>The reactions taking place are non-spontaneous</p> Signup and view all the answers

    A cell is prepared by dipping a copper rod in 1 M CuSO4 solution and an iron rod in 2 M FeSO4 solution. Identify the anode and cathode.

    <p>Anode-iron; cathode-copper</p> Signup and view all the answers

    Beer’s Law states that

    <p>Absorbance is proportional to the path length and concentration of the absorbing species</p> Signup and view all the answers

    Which of the following is the principle of Atomic Absorption Spectroscopy?

    <p>Radiation is absorbed by non-excited atoms in vapor state and are excited to higher states.</p> Signup and view all the answers

    Which of the following statements about mass spectroscopy is(are) correct?

    <p>all of the above</p> Signup and view all the answers

    The region of electromagnetic spectrum for NMR is

    <p>Radio frequency</p> Signup and view all the answers

    Which of the following is(are) application(s) of ion exchange chromatography?

    <p>All of the above</p> Signup and view all the answers

    Which of the following is widely used for the separation of specific biomolecules? This relies on the highly specific binding between an analyte and its counterpart.

    <p>Affinity chromatography</p> Signup and view all the answers

    What must be done to the solid samples for it to be introduced into the column without using solid injection syringes in gas chromatography

    <p>Dissolved in volatile liquids</p> Signup and view all the answers

    Which of the following is NOT an ideal characteristic of a detector used in gas chromatography?

    <p>Sensitive to the changes in the flow rate of a carrier gas</p> Signup and view all the answers

    Which of the following detectors is widely used to detect environmental samples like chlorinated pesticides and polychlorinated biphenyls?

    <p>Electron capture detector</p> Signup and view all the answers

    Which of the following is NOT true about the guard column used in liquid chromatography?

    <p>It allows entry of particles that cause precipitation upon contact with stationary or mobile phase</p> Signup and view all the answers

    Which of the following are not used in liquid or high performance liquid chromatography?

    <p>Capillary column</p> Signup and view all the answers

    Which treatment method is NOT typically used to remove organic compounds?

    <p>Thermal</p> Signup and view all the answers

    Segregation of waste organic solvents is very important because

    <p>All of the given answers</p> Signup and view all the answers

    Which method is considered an unacceptable means of disposing waste?

    <p>All methods given are unacceptable</p> Signup and view all the answers

    Which is the correct procedure for mixing acid and water?

    <p>Pour acid into water</p> Signup and view all the answers

    Which of these compounds exist as cis and trans isomers?

    <p>1-chloropropene</p> Signup and view all the answers

    Which compound will rapidly decolorize CHCl3 ?

    <p>1-hexene</p> Signup and view all the answers

    Baeyer’s reagent is used to characterize alkenes. Which of the following is Baeyer’s reagent?

    <p>Aqueous solution of potassium permanganate</p> Signup and view all the answers

    In what way does the reactivity of CH3C☰CH differ from CH3CH=CH2 ?

    <p>Propyne is deprotonated by NaNH2 while propene is not.</p> Signup and view all the answers

    Which of the following is an aromatic compound?

    <p>Styrene</p> Signup and view all the answers

    Which of the following is the most activating in electrophilic aromatic substitution?

    <p>-NH2</p> Signup and view all the answers

    Which of the following is the rate determining step in electrophilic aromatic substitution?

    <p>Addition of the electrophile in benzene's π bond to form carbocation</p> Signup and view all the answers

    Which of the following CANNOT be a product of the reaction of benzene with CH3Cl and AlCl3 ?

    <p>Isopropyl benzene</p> Signup and view all the answers

    Alkyl halides are very reactive towards nucleophiles because

    <p>They have a electrophilic carbon and a good leaving group</p> Signup and view all the answers

    SN2 means

    <p>One-step nucleophilic substitution involving both alkyl halide and nucleophile</p> Signup and view all the answers

    Which of the following alkyl halides can undergo both SN1 and SN2 reactions?

    <p>(CH3)2CHX</p> Signup and view all the answers

    Which of the following reactions are favored by polar aprotic solvent?

    <p>SN2 reactions</p> Signup and view all the answers

    Which compound has the highest boiling point?

    <p>CH3CH2CH2OH</p> Signup and view all the answers

    Which of the following reactions will NOT produce aldehydes?

    <p>Dehydration of secondary alcohols</p> Signup and view all the answers

    Carbon is found in the highest oxidation state in which of these classes of organic compounds?

    <p>Carboxylic acids</p> Signup and view all the answers

    Which reaction could occur between acetic acid and ethanol?

    <p>Esterification</p> Signup and view all the answers

    Which of the following reactions can be used to distinguish between phenol and carboxylic acids?

    <p>Aqueous FeCI3</p> Signup and view all the answers

    Under the Bronsted concept of acids and bases, a base is

    <p>proton acceptor</p> Signup and view all the answers

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