Description : Which of the following is the best nucleophile in water? (a) I– (b) CH3SCH3 (c) CH3OCH3 (d) Cl–
Last Answer : I–
Description : Which of the following is a Lewis acid? (a) AlCl3 (b) CH3OH (c) NH3 (d) CH3OCH3
Last Answer : AlCl3
Description : Which of the following is the strongest nucleophile in an aqueous solution? (a) HO– (b) Cl– (c) Br– (d) I
Description : Which of the following statements concerning SN2 reactions of alkyl halides is not correct? (a) The rate of reaction depends on the concentration of the nucleophile. (b) The rate of reaction depends on the ... carbon of the C-Br bond. (d) All alkyl iodides react more rapidly than all alkyl chlorides
Last Answer : All alkyl iodides react more rapidly than all alkyl chlorides
Description : Which of the following is not normally considered to be a nucleophile? (a) NH3 (b) CH3NH2 (c) HC≡C:– (d) CH3CH2+
Last Answer : CH3CH2+
Description : Which of the following is not a nucleophile? (a) NH3 (b) HSO3– (c) AlCl3 (d) HO–
Description : A cationic complex has two isomers A & B. Each has one Co3+, five NH3 , one Br and one SO4 2 . A gives a white precipitate with BaCl2 solution while B gives a yellow precipitate with AgNO3 ... are the possible structures of the complexes A and B ? (a) Will the two complexes have same colour ?
Last Answer : (a) [CO (NH3 ) 5 Br] SO4 and [CO (NH3 ) 5 SO4 ] Br (b) NO
Description : Which of the following is not an electrophile? (a) NH3 (b) Br+ (c) AlCl3 (d) NO2+
Last Answer : NH3
Description : Bromobenzene can be prepared by treating aniline with (a) Conc HBr (b) Br2/FeBr3 (b) CuBr (d) Nitrous acid then CuBr
Last Answer : Nitrous acid then CuBr
Description : Which of the reactions between the following pairs of reagents proceeds by a mechanism that may be described as an electrophilic substitution? (a) Benzene + Br2/FeBr3 (b) Propene + Br2 (c) Acetone + NH2NH2 (d) Ethyl bromide + aq KOH
Last Answer : Benzene + Br2/FeBr3
Description : Is FeBr3 ionic or molecular?
Last Answer : Iron(III) bromide is an ionic compound.
Description : Which compound has the highest boiling point? (a) CH3CH3 (b) CH3OCH3 (c) CH3CH2OH (d) CH3COOH
Last Answer : CH3COOH
Description : The compound in which hydrogen bonding is not possible is (a) CH3OCH3 (b) H2O (c) CH3CH2OH (d) CH3COOH
Last Answer : CH3OCH3
Description : The compound with the lowest boiling point is (a) H2O (b) CH3CH2OH (c) CH3OCH3 (d) CH3CH2CH3
Last Answer : CH3CH2CH3
Description : Which of the following pairs of compounds will not form hydrogen bonds with each other? (a) CH3OH and CH3CH2OH (b) CH3SH and CH3CH2SH (c) CH3OCH3 and CH3CH2OCH2CH3 (d) CH3COOH and H2O
Last Answer : CH3OCH3 and CH3CH2OCH2CH3
Description : Which of the following has the greatest solubility in CH3CH2CH2CH3? (a) CH3OH (b) CH3NH2 (c) CH3OCH3 (d) (CH3)3CH
Last Answer : (CH3)3CH
Description : Ethanol (CH3CH2OH) and dimethyl ether (CH3OCH3) are best considered : (a) structural isomers (b) stereoisomers (c) enantiomers (d) diastereomers
Last Answer : structural isomers
Description : Which of the following are Lewis bases? (a) NF3 (b) BF3 (c) CH3OCH3 (d) (a) and (c
Last Answer : (a) and (c
Description : Which one of the following substances will form strong hydrogen bonds? A HCOOH B CH3CN C CCl4 D SiH4 E CH3OCH3
Last Answer : A HCOOH
Description : Why cyanide ion act as ambident nucleophile ?
Last Answer : Ans.---- Cyanide ion can link through either carbon or nitrogen, therefore it is an ambident nuclophile.
Description : Which of the following is not a correct statement about the electrophilic substitution mechanism of benzene? (a) Benzene functions as a nucleophile. (b) Formation of a carbocation intermediate is the ... hybridized carbon in the ring. (d) The addition product is a frequently observed minor product.
Last Answer : The addition product is a frequently observed minor product.
Description : Why do aldehydes undergo nucleophilic addition reactions while esters undergo nucleophilic acyl substitution reactions? (a) The carbonyl carbon of an ester is more electrophilic than that of an aldehyde. (b) ... adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic
Last Answer : Once the nucleophile adds to an aldehyde, neither H− nor R− can be eliminated since they are strongly basic
Description : Which of the following factors has no effect on the rate of SN1 reactions? (a) the nature of the alkyl halide (b) the nature of the leaving group (c) the concentration of the alkyl halide (d) the concentration of the nucleophile
Last Answer : the concentration of the nucleophile
Description : Which of the following is the rate law for SN1 mechanisms? (a) Rate = k[Alkyl Halide] [Nucleophile] (b) Rate = k[Nucleophile] (c) Rate = k[Alkyl Halide] (d) Rate = k1[Alkyl Halide] + k2[Nucleophile]
Last Answer : Rate = k[Alkyl Halide]
Description : Which of the following factors influence whether a reaction will proceed by an SN1, SN2, E1, or E2 mechanism? (a) Structure of the alkyl halide (b) Solvent (c) Concentration of reagents (d) Nature of the nucleophile (e) All of these
Last Answer : All of these
Description : Which of the following is not a possible reaction of a carbocation? (a) addition of a nucleophile (b) rearrangement to a more stable carbocation (c) addition of a proton to form an alkane (d) loss of a β-hydrogen to form an alkene
Last Answer : addition of a proton to form an alkane
Description : Which of the following statements correctly describes the general reactivity of alkynes? (a) An alkyne is an electron-rich molecule and therefore reacts as a nucleophile. (b) The σ bonds ... fail to undergo electrophilic addition reactions. (d) Alkynes are generally more reactive than alkenes.
Last Answer : Alkynes are generally more reactive than alkenes.
Description : Why does a H+ ion attacking a carbon-carbon double bond add to the carbon with the least number of substituents? (a) the reaction is resonance stabilized. (b) the hybrid geometry favors this ... tends to attack stable centers of negative charge. (d) a more stable carbonium ion is generated.
Last Answer : a more stable carbonium ion is generated.
Description : In the reaction of propene with HCl, H+ ion acts as the : (a) electrophile (b) carbonium ion (c) nucleophile (d) carbanion
Last Answer : electrophile
Description : Which of the following statements is incorrect? (a) Electrons move toward positively charged locations. (b) An electron-rich atom is called an electrophile. (c) An electrophile is electron loving. (d) A nucleophile has a a pair of electrons it can share
Last Answer : An electron-rich atom is called an electrophile.
Description : A nucleophile acts as a __________ when it reacts with an electrophile. (a) Bronsted-Lowry acid (b) Arrhenius base (c) Lewis acid (d) Lewis base
Last Answer : Lewis base
Description : An electrophile acts as a __________ when it reacts with a nucleophile. (a) Bronsted-Lowry base (b) Arrhenius base (c) Lewis acid (d) Lewis base
Last Answer : Lewis acid
Description : Which of the following is a nucleophile? (a) AlCl3 (b) H3O+ (c) BF3 (d) CN–
Last Answer : CN–
Description : When semicarbazide reacts with a ketone (or aldehyde) to form semicarbazone. Only one nitrogen atom of semicarbazide acts as a nucleophile and attack
Last Answer : When semicarbazide reacts with a ketone (or aldehyde) to form semicarbazone. Only one ... atoms of semicarbazide are relatively non nucleophilic ?
Description : Which of the following is not a nucleophile ?
Last Answer : Which of the following is not a nucleophile ? A. `H_(2)` B. `CH_(3)OH` C. `H_(2)O` D. `NH_(3)`
Description : Which among the following compounds behave both as an electrophile as well a nucleophile? `{:(underset("(1)")(CH_(2)=CH_(2))" "underset("(2)")(CH_(2)=
Last Answer : Which among the following compounds behave both as an electrophile as well a nucleophile? `{:(underset("(1)")(CH_(2)= ... and (4) D. (2), (3) and (4)
Description : `NH_(3) + NaOCl overset("golatin or " EDTA^(+))rarr` products The number of moles of `N - H` bonds present in one mole of the strongest nucleophile pr
Last Answer : `NH_(3) + NaOCl overset("golatin or " EDTA^(+))rarr` products The number of moles of ... mole of the strongest nucleophile present in the product is:
Description : Which of the following are nucleophile?
Last Answer : Which of the following are nucleophile? A. `NH_(3)` B. `OH^(-)` C. `R-O-R` D. `AlCl_(3)`
Description : A nucleophile must have :
Last Answer : A nucleophile must have : A. a negative charge B. a positive charge C. a lone pair of electron D. an electron deficient centre
Description : Which one of the following behaves both as a nucleophile and an electrophile ?
Last Answer : Which one of the following behaves both as a nucleophile and an electrophile ? A. `CH_(3)NH_(2)` B. `CH_(3)OH` C. `CH_(3)CN` D. `CH_(3)Cl`
Description : A nucleophile is:
Last Answer : A nucleophile is: A. electron-rich species B. electron-deficient species C. a Lewis base D. positively charged species
Description : The most electropositive elements among the following is : (1) Cs (2) Ca (3) Na (4) Br
Last Answer : (1) Cs Explanation: The alkali metals are the most electropositive. Cesium is the most electropositive of the stable elements.Francium, while unstable, is theoretically the most electropositive element.
Description : Identify the result of chemical reaction between permanganate ion and Br- ?
Last Answer : Ans. MnO2 and BrO3 - are formed.
Description : From the elements: Cl, Br, F, O, Al, C, Li, Cs and Xe; choose the following: (a) The element with highest negative electron gain enthalpy. (b) The element with lowest ionization enthalpy. ( ... . (f)The element which belongs to zero group. (g) The elements which forms largest number of compounds.
Last Answer : Ans. (a). The element chlorine (Cl) has the highest negative electron gain enthalpy. (b). The element cesium (Cs) has lowest ionization enthalpy. (c). The element fluorine F has lowest atomic radius. (d ... zero group (or group 18). (g). The element carbon (C) forms the largest number of compounds.
Description : The increasing order of reactivity among group 1 elements is Li
Last Answer : Ans. In group 1 elements (alkali metals) the reactivity of the metals is mainly due to the electron releasing tendency of their atoms, which is related to ionization enthalpy, Since ... electron gain enthalpy. Since both of them decrease down the group, the reactivity therefore decreases.
Description : Arrange the following order of the property indicated: (a). F, Cl, Br and I (negative electron gain enthalpy) (b). Mg, Al, Si and Na (ionization enthalpy) (c). C, N, O and F (second ionization enthalpy)
Last Answer : Ans. (a). I
Description : (a) If the radius of the Br ion is 0.182 nm, how large a cation can fit in each of the tetrahedral hole. (b) AgI crystallizes in a cubic closed packed ZnS structure. What fraction of tetrahedral site ... Ag ion ? (c) At what temp. range, most of the metals becomes super conductors ?
Last Answer : (a) For a tetrahedron the limiting ratio is 0.225 – 0.414 For largest cation highest value 0.414 would be considered. r + / r– = 0.414 r + = 0.414 × 0.182 = 0.075 nm. (b) In FCC there are 8 tetrahedral voids. Out of this ½ is occupied by Ag cation. (c) 2 k – 5 k.