MDCAT Chemistry Online Test With Answers

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MDCAT Chemistry Online Test

Sr. # Questions Answers Choice
1
To prepare ethane by Wurtz synthesis the suitable alkyl halide is
 Ethyl iodide any alkyl iodide Ethyl chloride Methyl bromide
2 Reaction of ethyl bromide with ammonia <div>Completes in a single step</div><div><br></div> Completes in two steps Continues till N is left with no lone pair is reversible
3 In beta elimination reaction carbon number changes unsaturated compound is formed hybridization. ofC remains same pi bonds are decreased
4 Which is an intermediate in SN1 reaction Ethoxide ion Carbocation alkyl halide alkene
5 The reagent for alkaline hydrolysis of ethyl bromide to form ethyl alcohol is water at room T Alcoholic KOH+heat Ethanol + heat dil. NaOH+ heat
6 Which pair gives same dehydrohalogenation product <div>I-Chlorobutane, 2-Chlorobutane</div><div><br></div> I-Chloropropane, 2-Chloropropane I-Bromopentane. 3-Bromopentane iso-butvl chloride. 2°- butyl chloride
7 In an elimination reaction a more substituted alkene is formed due to the stability associated with Free radical transition state Activated complex Carbocation
8 Dehydrohalogenation of secondary butyI bromide will give Propene 1-Butene Butene 2-Butene
9 Which of the following reactants will be required to form ethene from ethyl chloride <sub>Alcoholic KOH</sub> Alkaline KMnO4 Aqucous KOH Aqucous NaOH
10 Which one among the following is not a good leaving group HSO4- CI- OH- Br-
11 In nucleophilie substitution bimolecular reaction the order of reaction with respect to substrate 2 order 3 order 1st order Zero order
12 Which compound is obtained hy the elimination reaction on bromoethane? Butene Ethene Propene Propane
13 When 2-bromobutane reacts with alcoholic KOH, the reaction is called Chlorination Halogenation Dehydrohalogenation Hydrogenation
14 Which of the following alkyl halides undergoes SN1 reaction fastest Methyl chloride Isobutyl chlorido Ethy l chloride Tertiary butyl chloride
15 A mixture of 1-chloropropane and 2-chloro-propane when treated with alcoholic KOH, gives Prop-2-ene Isopropy lene Propene A mixture of prop-l-ene
16 In elimination reaction i.e, in the formation of alkene, the reactivity of alkyl halide is in the order: CI&gt;Br&gt;I I&gt;Br&gt;Cl Br&gt;CI&gt;I I&gt;CI&gt; Br
17 The species which are produced by heterolytic bond breaking and can act as electron pair donor Free radicals Cations Nucleophiles electrophile
18 Among the following, which one is nucleophile H+ Ca2+ OH- Na+
19 Which is an intermediate in Svl Ethoxide ion Alkene Alkyl halide Carbocation
20 Which one of the following is NOT a nucleophile NH2+ BF3 H2O CH3-
21 The order of reactivitv of alksI halides towards nucleophile is RI&gt;RBr RF&gt;RCI RF&gt;RCI&gt;RBr&gt;RI RI&gt;RBr&gt; RCI&gt;RE RF&gt;RBr&gt;RCI&gt;RI
22
The alkaline hydrolysis of bromoethane shown below gives alcohol as the product: H3C-CH2-Br-------H3C-CH2-OH
The reagent and the condition used in this reaction may be:
 H20 at room temperature KOH in alcohol Ethanol. heat Dilute NaOH(aq) warm
23 When purely alcoholic solution of sodium/potassiumhydroxide and halogenoalkanes are reacted an alkene is formed, what is the mechanism of reaction? Elimination Debromination Dehydration Reduction
24 Correct order for the reactivity ofalkyl halide in S, reactions R-I&gt;R-F&gt;R-CI R-F&gt;R-CI&gt;R-I R-I&gt;R-CI&gt;R-F R-CI&gt;R-I&gt;R-F
25 Correct statement about Nucleophilic substitution bimolecular is Transition state is formed Inversion take place It is two step reacticn Both a &amp;c
26 The reaction C2H5CI + aqueous KOH---------C2H5OH+ KCI is Electrophilic addition Nucleophilic addition Electrophilic substitution Nucleophilic substitution
27 An alkyl halide reacts with NH3 to give Amide Cyanide Amine Aniline
28 Out of monochloro, monobromo and mongiodo derivatives of ethane, the mos reactive compound towards nucleophilic substitution will be C2H5Br C2H5Cl C2H5I All are equally reactive
29 Elimination unimolecular reactions involve Second order kinetics First order kinetics Third order kinetics Zero order kinetics
30 Which of the following is primary alkyl halide IsopropyI halide Sec-butyl halide Tert-buryi halide Neo-pentyl halide
31 Which isomer of C4H9Br will produce 2-methyl propane-2-ol on treatment with aqueous KOH n-butyI bromide Sec-butyI bromide Isobutyl halide Tertiary butyl chloride
32 Which one of the following is not associated with SN2 mechanism 100 % inversion of configuration Tertiar alkyI halides 2nd order kinetics Change of hy bridization from sp³ to sp² in transition state
33 Which of the following factors does not affect the SN1 rate is Nucleophilicity of the attacking nucleophile Stability of the carbonium ion Solvent system The nature of leaving group
34 In the transition state of S2 mechanism reaction with alkyl halides, which of the following orbital hybridization is involved sp³ sp sp² dsp³
35 Which of the following decides the reactivity of alkyl halides? C-C bond strength C-H bond strength C-X bond strength Electronegativity difference
36 Chloroform (CHCl3) is? Primary alkyl halide Secondary alkyl halide Tertiary alkyl halide a liquid
37 Which is a good nucleophile as well as a good leaving group? F- Cl- Br- I-
38 An amine is produced in the following reaction
C2H5l+2NH3-------C2H5NH2 +NH4l. What is mechanism?		 Electrophilic addition Electrophilic substitution Nucleophilic addition Nucleophilic substitution
39 The Sl mechanism for the hydrolysis of an alkyl halide to an alcohol involves the formation of Carbocation Carbanion Pentavalent carbon in the transition state Free radical
40 SN2-reactions can be usually observed in Primary alkylı halide secondary alkyl halide Tertiary alkyl halide Both A. and B
41 Alkyl halides are considered to be very reactive compounds towards nucleophiles, because The have an electrophilic carbon They have an electrophilic carbon and a bad leaving group They have an electrophilic carbon and a good laving group They have a nucleophilic carbon and a good leaving group
42 The rate of E1 reaction depends upon The concentration of substrate The concentration of substrate as well as nucleophile The concentration Nucleophilic Nature of Catalyst
43 For which mechanisms, the first step involved is the same E1 and E2 E2 and SN2 E2 and E1 E1 and SN1
44 The average bond energy of C-Br is 228 kJmol-1 250 kJmol-1 200 kJmol-1 290 kJmol-1
45 The carbon atom of an alkyl group attached with halogen atom is called Electrophile Free redical Nucleophile Nucleophilic centre
46 Hydration of ethene is an example of Electrophilic addition Electrophilic substitution Nucleophilic addition Nucleophilic substitution
47 Ethyl and methyl groups are equidistant in a chain, the preference is given to? Ethyl methyl both ethyl and methyl methyl mostly
48 Tertiary alcohols are the easiest to dehydrate because They form stable carbocation They have less hydrogen They have bigger size They are polar
49 The reaction of alkyl halide in the presence of alcoholic KOH is Substitution Addition Acid-base Elimination
50 Which group activates the benzene ring -COOH -COR -CHO -OH
51 Benzene reacts with Ethyl chloride in presence of AICls to give Benzalchloride Benzyl chloride Ethyl benzene Benzotrichloride
52 Ethene can give all of the following reactions except Addition Free radical substitution Hydrohalogenation Hydration
53 Active sulphonating agent during sulphonation of benzene is SO2 SO3 SO3H SO3+
54 Glyoxal molecule has? two carbonyl groups One aldehydic and one carbonyl group Two aldehydic groups Two carboxyl group
55 Ethane when completely halogenated in excess of chiorine can form Hexachloroethane Dichloroethane Pentachloroethane 1.1.2.2-terachloroethane
56 The origin ofacidic nature of alkyne is? small size of C Small size of H polarity of triple bond sp hybridization
57 A compound that has a nucleophilic carbon? C2H2 C2H4 C3H8 C6H6
58 The addition of HCI to ethene gives? Chloroethane 1,2-dichloroethane 1.1-dichloroethane 2-chloroethane
59 The reaction that generates an ionic bond is Halogenation of ethene polymerization of ethene Hydrogenation of ethyne Reaction of ethyne withs sodamide
60 Acetylide can give back ethyne upon treatment with water strong base dil. Acid weak base
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