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MCQOPTIONS
This section includes 1187 Mcqs, each offering curated multiple-choice questions to sharpen your NEET knowledge and support exam preparation. Choose a topic below to get started.
| 251. |
Which of the following is (are) true concerning the intermediate in the addition-elimination mechanism of the following reaction? A = The intermediate is aromatic, B = The intermediate is a resonance stabilised anion, C = Electron withdrawing groups on the benzene ring stabilises the intermediate |
| A. | only A |
| B. | only B |
| C. | A and C |
| D. | B and C |
| Answer» E. | |
| 252. |
Although hexafluoroethane \[({{C}_{2}}{{F}_{6}},b.p.-79{}^\circ C)\] and ethane \[({{C}_{2}}{{H}_{6}},b.p.-89{}^\circ C)\] differ very much in their molecular weights, their boiling points differ only by\[10{}^\circ C\]. This is due to |
| A. | lowpolarizability of F |
| B. | nearly similar size of F and H |
| C. | both [a] and [b] |
| D. | Neither of the two |
| Answer» D. Neither of the two | |
| 253. |
The following reaction proceeds through the intermediate formation of \[RCOOAg+B{{r}_{2}}\xrightarrow{{}}RBr+C{{O}_{2}}+AgBr\] |
| A. | \[RCO{{O}^{\bullet }}\] |
| B. | \[{{R}^{\bullet }}\] |
| C. | \[B{{r}^{\bullet }}\] |
| D. | All of these |
| Answer» E. | |
| 254. |
The compound \[{{C}_{7}}{{H}_{8}}\xrightarrow{3C{{l}_{2}}/\Delta }A\xrightarrow{B{{r}_{2}}/Fe}B\xrightarrow{Zn/HCl}C\]. The compound C is |
| A. | o-Bromotoluene |
| B. | m-Bromotoluene |
| C. | p-Bromotoluene |
| D. | 3-Bromo-2,4,6-trichlorotoluene |
| Answer» C. p-Bromotoluene | |
| 255. |
The Wurtz-Fittig reaction involves condensation of |
| A. | two molecules of aryl halides. |
| B. | one molecule of each of aryl-halide and alkyl-halide. |
| C. | one molecule of each of aryl-halide and phenol. |
| D. | two molecules of aralkyl-halides. |
| Answer» C. one molecule of each of aryl-halide and phenol. | |
| 256. |
The major product of the following reaction is: \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}-\underset{Br}{\overset{C{{H}_{3}}}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-C{{H}_{2}}-C{{H}_{3}}\xrightarrow[{{C}_{2}}{{H}_{5}}OH]{{{C}_{2}}{{H}_{5}}ONa}\] |
| A. | \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}-\underset{O{{C}_{2}}{{H}_{5}}}{\overset{C{{H}_{3}}}{\mathop{\underset{|}{\overset{|}{\mathop{C}}}\,}}}\,-C{{H}_{2}}-C{{H}_{3}}\] |
| B. | \[{{C}_{6}}{{H}_{5}}CH=\underset{C{{H}_{3}}}{\overset{{}}{\mathop{\underset{|}{\overset{{}}{\mathop{C}}}\,}}}\,-C{{H}_{2}}-C{{H}_{3}}\] |
| C. | \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}-\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{C}}\,}}\,=CHC{{H}_{3}}\] |
| D. | \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}-\underset{C{{H}_{2}}C{{H}_{3}}}{\overset{{}}{\mathop{\underset{|}{\overset{{}}{\mathop{C}}}\,}}}\,=C{{H}_{2}}\] |
| Answer» C. \[{{C}_{6}}{{H}_{5}}C{{H}_{2}}-\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{C}}\,}}\,=CHC{{H}_{3}}\] | |
| 257. |
Which of the following order is not correct? |
| A. | \[MeBr>M{{e}_{2}}CHBr>\] \[M{{e}_{3}}CBr>E{{t}_{3}}CBr\left( {{S}_{N}}2 \right)\] |
| B. | \[PhC{{H}_{2}}Br>Ph\,CHBrMe>PhCBrM{{e}_{2}}>\]\[PhCBrMePh\left( {{S}_{N}}1 \right)\] |
| C. | \[MeI>MeBr>MeCl>MeF({{S}_{N}}2)\] |
| D. | All are correct |
| Answer» C. \[MeI>MeBr>MeCl>MeF({{S}_{N}}2)\] | |
| 258. |
In the following reaction sequence: \[\underset{({{C}_{3}}\overset{{}}{\mathop{{{H}_{6}}}}\,C{{l}_{2}})}{\mathop{I}}\,\xrightarrow{KOH(aq)}II\xrightarrow[(ii){{H}_{2}}O/{{H}^{+}}]{(i)C{{H}_{3}}MgBr}III\] \[\xrightarrow{Anhy.ZnC{{l}_{2}}+Conc.HCl}given\,turbidity\,immediately\] The compound I is: |
| A. | \[\underset{Cl}{\mathop{\underset{|}{\mathop{C}}\,}}\,{{H}_{2}}-\underset{Cl}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-C{{H}_{3}}\] |
| B. | \[\underset{Cl}{\mathop{\underset{|}{\mathop{C}}\,}}\,{{H}_{2}}-\underset{{}}{\mathop{\underset{{}}{\mathop{C}}\,}}\,{{H}_{2}}-\underset{Cl}{\mathop{\underset{|}{\mathop{C}}\,}}\,{{H}_{3}}\] |
| C. | \[Cl-\underset{Cl}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-C{{H}_{2}}-C{{H}_{3}}\] |
| D. | \[C{{H}_{3}}-\underset{Cl}{\mathop{\overset{Cl}{\mathop{\underset{|}{\mathop{\overset{|}{\mathop{C}}\,}}\,}}\,}}\,-C{{H}_{3}}\] |
| Answer» E. | |
| 259. |
In the following sequence of reactions \[\underset{A}{\mathop{C{{H}_{3}}C{{H}_{2}}I}}\,\xrightarrow[ether]{Mg}B\xrightarrow{HCHO}C\xrightarrow{{{H}_{2}}O}D\] the compound D is |
| A. | propanal |
| B. | butanal |
| C. | n-butyl alcohol |
| D. | n-propyl alcohol |
| Answer» E. | |
| 260. |
Identify correct reactivity order for \[{{S}_{N}}1\] reaction (i) (ii) (iii) |
| A. | i>ii>iii |
| B. | ii>iii>i |
| C. | i>iii>ii |
| D. | iii>ii>i |
| Answer» E. | |
| 261. |
\[C{{H}_{3}}C{{H}_{2}}Cl\xrightarrow{NaCN}X\xrightarrow{Ni/{{H}_{2}}}\]\[Y\xrightarrow[anhydride]{Acetic}Z\] Z in the above reaction sequence is |
| A. | \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}NHCOC{{H}_{3}}\] |
| B. | \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}N{{H}_{2}}\] |
| C. | \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}CONHC{{H}_{3}}\] |
| D. | \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}CONHCOC{{H}_{3}}\] |
| Answer» B. \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}N{{H}_{2}}\] | |
| 262. |
Among the given halides, which one will give same product in both \[{{S}_{N}}1\] and \[{{S}_{N}}2\] reactions? (I) \[C{{H}_{3}}-\overset{C{{H}_{3}}}{\mathop{\overset{|}{\mathop{C}}\,}}\,H-C{{H}_{2}}-\underset{Br}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-C{{H}_{3}}\] (II) (III) (IV)\[C{{H}_{3}}-\underset{Et}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-Br\] |
| A. | (III) only |
| B. | (I) and (II) |
| C. | (III) and (IV) |
| D. | (I), (III) and (IV) |
| Answer» D. (I), (III) and (IV) | |
| 263. |
2-Bromopentane is heated with potassium ethoxide in ethanol. The major product obtained is |
| A. | 2-Ethoxypentane |
| B. | Pentene-1 |
| C. | cis-Pentene-2 |
| D. | trans-Pentene-2 |
| Answer» E. | |
| 264. |
The reaction conditions leading to the best yields of \[{{C}_{2}}{{H}_{5}}Cl\] are: |
| A. | \[{{C}_{2}}{{H}_{6}}(excess)+C{{l}_{2}}\xrightarrow{UV\,light}\] |
| B. | \[{{C}_{2}}{{H}_{6}}+C{{l}_{2}}\xrightarrow[room\text{ }temperature]{dark}\] |
| C. | \[{{C}_{2}}{{H}_{6}}+C{{l}_{2}}(excess)\xrightarrow{UV\,light}\] |
| D. | \[{{C}_{2}}{{H}_{6}}+C{{l}_{2}}\xrightarrow{UV\,light}\] |
| Answer» B. \[{{C}_{2}}{{H}_{6}}+C{{l}_{2}}\xrightarrow[room\text{ }temperature]{dark}\] | |
| 265. |
Which compound in each of the following pairs is most reactive to the conditions indicated? [A] and [B] [C] and [D] |
| A. | A and C |
| B. | B and C |
| C. | A and D |
| D. | B and D |
| Answer» B. B and C | |
| 266. |
\[C{{H}_{3}}-C{{H}_{2}}-\underset{Cl}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-C{{H}_{3}}\] obtained by chlorination of n-butane, will be |
| A. | meso-form |
| B. | racemic mixture |
| C. | d-form |
| D. | l-form |
| Answer» C. d-form | |
| 267. |
Replacement of \[Cl\] of chlorobenzene to give phenol requires drastic conditions but chlorine of 2,4-dinitrochlorobenzene is readily replaced. This is because |
| A. | \[N{{O}_{2}}\] makes the ring electron rich at ortho and para positions. |
| B. | \[N{{O}_{2}}\] withdraws \[{{e}^{-}}\] from meta-position. |
| C. | \[N{{O}_{2}}\] donates \[{{e}^{-}}\] at meta-position. |
| D. | \[N{{O}_{2}}\] withdraws \[{{e}^{-}}\] from ortho/para-positions. |
| Answer» E. | |
| 268. |
Which chloride is least reactive with the hydrolysis point of view? |
| A. | \[C{{H}_{3}}Cl\] |
| B. | \[C{{H}_{3}}C{{H}_{2}}Cl\] |
| C. | \[{{\left( C{{H}_{3}} \right)}_{3}}CCl\] |
| D. | \[C{{H}_{2}}=CH-Cl\] |
| Answer» E. | |
| 269. |
Identify Z in the following serie's \[{{C}_{2}}{{H}_{5}}\xrightarrow{Alc.KOH}X\xrightarrow{B{{r}_{2}}}Y\xrightarrow{KCN}Z\] |
| A. | \[C{{H}_{3}}C{{H}_{2}}CN\] |
| B. | \[NCC{{H}_{2}}-C{{H}_{2}}CN\] |
| C. | \[BrC{{H}_{2}}-C{{H}_{2}}CN\] |
| D. | \[BrCH=CHCN\] |
| Answer» C. \[BrC{{H}_{2}}-C{{H}_{2}}CN\] | |
| 270. |
Among the following, the molecule with the lowest dipole moment is |
| A. | \[CHC{{l}_{3}}\] |
| B. | \[C{{H}_{3}}Cl\] |
| C. | \[C{{H}_{2}}C{{l}_{2}}\] |
| D. | \[CC{{l}_{4}}\] |
| Answer» E. | |
| 271. |
Which one of the following reagents is not suitable for the elimination reaction? |
| A. | NaI/acetone |
| B. | NaOEt/EtOH |
| C. | \[NaOH/{{H}_{2}}O\] |
| D. | \[NaOH/{{H}_{2}}O-EtOH\] |
| Answer» B. NaOEt/EtOH | |
| 272. |
The total number of acyclic isomers including the stereoisomers with the molecular formula \[{{C}_{4}}{{H}_{7}}Cl\] |
| A. | 11 |
| B. | 12 |
| C. | 9 |
| D. | 10 |
| Answer» C. 9 | |
| 273. |
Pure chloroform is prepared by |
| A. | distilling chloral hydrate with aqueous sodium hydroxide. |
| B. | heating ethanol with bleaching powder. |
| C. | heating acetone with bleaching powder. |
| D. | reducing carbon tetrachloride. |
| Answer» B. heating ethanol with bleaching powder. | |
| 274. |
\[C{{H}_{3}}Br+N{{u}^{-}}\xrightarrow{{}}C{{H}_{3}}-Nu+B{{r}^{-}}\] The decreasing order of the rate of the above reaction with nucleophiles \[\left( N{{u}^{-}} \right)\] A to D is \[[N{{u}^{-}}=(A)Ph{{O}^{-}},(B)Ac{{O}^{-}},(C)H{{O}^{-}},(D)C{{H}_{3}}{{O}^{-}}]\] |
| A. | \[A>B>C>D\] |
| B. | \[B>D>C>A\] |
| C. | \[~D>C>A>B\] |
| D. | \[D>C>B>A\] |
| Answer» D. \[D>C>B>A\] | |
| 275. |
Aryl fluoride may be prepared from arene diazonium chloride using: |
| A. | \[HB{{F}_{4}}/\Delta \] |
| B. | \[HB{{F}_{4}}/NaN{{O}_{2}},Cu,\Delta \] |
| C. | \[CuF/HF\] |
| D. | \[Cu/HF\] |
| Answer» B. \[HB{{F}_{4}}/NaN{{O}_{2}},Cu,\Delta \] | |
| 276. |
The chief reaction product of reaction between n-butane and bromine at 573K is: |
| A. | \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}C{{H}_{2}}Br\] |
| B. | \[C{{H}_{3}}C{{H}_{2}}\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{C}}\,}}\,HBr\] |
| C. | \[C{{H}_{3}}-C{{H}_{2}}\underset{C{{H}_{2}}Br}{\mathop{\underset{|}{\mathop{C}}\,}}\,HBr\] |
| D. | \[C{{H}_{3}}C{{H}_{2}}\underset{C{{H}_{3}}}{\mathop{\underset{|}{\mathop{C}}\,}}\,Br\] |
| Answer» C. \[C{{H}_{3}}-C{{H}_{2}}\underset{C{{H}_{2}}Br}{\mathop{\underset{|}{\mathop{C}}\,}}\,HBr\] | |
| 277. |
Arrange the following compounds in order of increasing dipole moment: (I) Toluene(II) m-dichlorobenzene(III) o-dichlorobenzene(IV) p-dichlorobenzene |
| A. | \[I<IV<II<III\] |
| B. | \[IV<I<II<III\] |
| C. | \[IV<I<III<II\] |
| D. | \[IV<II<I<III\] |
| Answer» C. \[IV<I<III<II\] | |
| 278. |
Which of the following statements regarding electrolytic refining of copper is incorrect? |
| A. | In this process anode is made up of impure copper and pure copper strips are taken as cathode. |
| B. | Acidic or basic solution of copper sulphate is used as electrolyte |
| C. | Antimony, tellurium, silver and gold are some of the metals deposits as anode mud during this process |
| D. | Zinc can be also refined by electrolytic refining method. |
| Answer» C. Antimony, tellurium, silver and gold are some of the metals deposits as anode mud during this process | |
| 279. |
Which of the following condition favours the reduction of a metal oxide to metal? |
| A. | \[\Delta H=+ve,T\Delta S=+ve\] at low temperature |
| B. | \[\Delta H=+ve,T\Delta S=-ve\] at any temperature |
| C. | \[\Delta H=-ve,T\Delta S=-ve\] at high temperature |
| D. | \[\Delta H=-ve,T\Delta S=+ve\] at any temperature |
| Answer» E. | |
| 280. |
Which of the following metals is extracted by the electrometallurgical method? |
| A. | Cu |
| B. | Fe |
| C. | Na |
| D. | Ag |
| Answer» D. Ag | |
| 281. |
The most electropositive metals are isolated from their ores by |
| A. | high temperature reduction with carbon |
| B. | self reduction |
| C. | thermal decomposition |
| D. | electrolysis of fused ionic salts |
| Answer» E. | |
| 282. |
Cassiterite is concentrated by |
| A. | levigation |
| B. | electromagnetic separation |
| C. | floatation |
| D. | liquefaction |
| Answer» C. floatation | |
| 283. |
In the electrolysis of alumina to obtain aluminiumb metal, cryolite is added mainly to |
| A. | lower the melting point of alumina |
| B. | dissolve alumina in molten cryolite |
| C. | remove the impurities of alumina |
| D. | increase the electrical conductivity |
| Answer» B. dissolve alumina in molten cryolite | |
| 284. |
Purification of silicon element used in semiconductors is done by |
| A. | zone refining |
| B. | heating |
| C. | froth floatation |
| D. | heating in vacuum |
| Answer» B. heating | |
| 285. |
\[{{\Delta }_{f}}G{{~}^{-}}vs\]T plot in the Ellingham diagram slopes downward for the reaction |
| A. | \[Mg+\frac{1}{2}{{O}_{2}}\to MgO~\] |
| B. | \[2Ag+\frac{1}{2}{{O}_{2}}\to A{{g}_{2}}O\] |
| C. | \[C+\frac{1}{2}{{O}_{2~}}\to CO\] |
| D. | \[CO+\frac{1}{2}{{O}_{2~}}\to C{{O}_{2}}\] |
| Answer» D. \[CO+\frac{1}{2}{{O}_{2~}}\to C{{O}_{2}}\] | |
| 286. |
The method of zone refining of metals is based on the principle of: |
| A. | Greater solubility of the impurity in the molten state than in the solid |
| B. | Greater mobility of the pure metal than that of the impurity |
| C. | Higher melting point of the impurity than that of the pure metal |
| D. | Greater noble character of the solid metal than that of the impurity |
| Answer» B. Greater mobility of the pure metal than that of the impurity | |
| 287. |
Complexes formed in the following methods areI.Mond's process for purification of nickel.II.Removal of lead poisoning from the body.III.Cyanide process for extraction of silver.IV.Froth flotation process for separation of ZnS from galena ore by using depressant. |
| A. | I.II.III.IV. \[Ni{{\left( CO \right)}_{4}}\]\[[Pb{{\left( EDTA \right]}^{2-}}\]\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]\[[Zn{{(CN)}_{2}}]\] |
| B. | I.II.III.IV. \[Ni{{\left( CO \right)}_{4}}\]\[[Pb{{\left( EDTA \right]}^{2-}}\]\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]\[{{[Zn{{(CN)}_{4}}]}^{2-}}\] |
| C. | I.II.III.IV. \[Ni{{\left( CO \right)}_{6}}\]\[[Pb{{\left( EDTA \right]}^{4-}}\]\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]\[{{[Zn{{(CN)}_{6}}]}^{4-}}\] |
| D. | I.II.III.IV. \[Ni{{\left( CO \right)}_{4}}\]\[[Pb{{\left( EDTA \right]}^{2-}}\]\[{{[Ag{{\left( CN \right)}_{4}}]}^{3-}}\]\[{{[Zn{{(CN)}_{4}}]}^{2-}}\] |
| Answer» C. I.II.III.IV. \[Ni{{\left( CO \right)}_{6}}\]\[[Pb{{\left( EDTA \right]}^{4-}}\]\[{{[Ag{{\left( CN \right)}_{2}}]}^{-}}\]\[{{[Zn{{(CN)}_{6}}]}^{4-}}\] | |
| 288. |
Heating pyrites to remove sulphur is called |
| A. | smelting |
| B. | calcination |
| C. | liquation |
| D. | roasting |
| Answer» E. | |
| 289. |
Which of the following reactions is an example for calcination process? |
| A. | \[2Ag+2HCl+(O)\to 2AgCl+{{H}_{2}}O\] |
| B. | \[2Zn+{{O}_{2}}\to 2ZnO\] |
| C. | \[2ZnS+3{{O}_{2}}\to 2ZnO+2S{{O}_{2}}\] |
| D. | \[MgC{{O}_{3}}\to MgO+C{{O}_{2}}\] |
| Answer» E. | |
| 290. |
Which one of the following ores is not concentrated by froth floatation process? |
| A. | Copper pyrites |
| B. | Pyrargyrite |
| C. | Pyrolusite |
| D. | Zinc blende |
| Answer» D. Zinc blende | |
| 291. |
The substance used as froth stabilisers in froth- floatation process is |
| A. | Potassium ethyl xanthate |
| B. | Aniline |
| C. | Sodium cyanide |
| D. | Copper sulphate |
| Answer» C. Sodium cyanide | |
| 292. |
Extraction of zinc from zinc blende is achieved by |
| A. | roasting followed by self-reduction |
| B. | electrolytic reduction |
| C. | roasting followed by reduction with carbon |
| D. | roasting followed by reduction with another metal |
| Answer» D. roasting followed by reduction with another metal | |
| 293. |
Which of the oxide groups among the following cannot be reduced by carbon? |
| A. | \[C{{u}_{2}}O,Sn{{O}_{2}}\] |
| B. | \[CaO,{{K}_{2}}O\] |
| C. | \[PbO,F{{e}_{2}}{{O}_{4}}\] |
| D. | \[F{{e}_{2}}{{O}_{3}},ZnO\] |
| Answer» C. \[PbO,F{{e}_{2}}{{O}_{4}}\] | |
| 294. |
In Hall-Heroult process how much carbon anode is burnt away to produce each 1kg of aluminium? |
| A. | 0.3kg |
| B. | 0.5kg |
| C. | 1kg |
| D. | 0.1kg |
| Answer» C. 1kg | |
| 295. |
When the sample of copper with zinc impurity is to be purified by electrolysis, the appropriate electrodes are |
| A. | CathodeAnodePure zincPure copper |
| B. | CathodeAnodeImpure samplePure copper |
| C. | CathodeAnodeImpure sampleImpure sample |
| D. | CathodeAnodePure copperImpure sample |
| Answer» E. | |
| 296. |
In electro-refining of metal the impure metal is made the anode and a strip of pure metal, the cathode, during the electrolysis of an aqueous solution of a complex metal salt. This method cannot be used for refining of |
| A. | silver |
| B. | copper |
| C. | aluminium |
| D. | sodium |
| Answer» E. | |
| 297. |
The process of converting hydrated alumina into anhydrous alumina is called |
| A. | roasting |
| B. | smelting |
| C. | dressing |
| D. | calcination |
| Answer» E. | |
| 298. |
\[XC{{l}_{2}}(excess)+YC{{l}_{2}}\xrightarrow{{}}XC{{l}_{4}}+Y\downarrow ;\] \[YO\xrightarrow[>400{}^\circ ]{\Delta }\frac{1}{2}{{O}_{2}}+Y,\] Ore of Y would be: |
| A. | Siderite |
| B. | Cinnabar |
| C. | Malachite |
| D. | Hornsilver |
| Answer» C. Malachite | |
| 299. |
In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with: |
| A. | Copper (I) sulphide \[(C{{u}_{2}}S)\] |
| B. | Sulphur dioxide \[\left( S{{O}_{2}} \right)\] |
| C. | Iron sulphide \[\left( FeS \right)\] |
| D. | Carbon monoxide (CO) |
| Answer» B. Sulphur dioxide \[\left( S{{O}_{2}} \right)\] | |
| 300. |
In electrorefining of copper some gold is deposited as |
| A. | anode mud |
| B. | cathode mud |
| C. | electrolyte |
| D. | None of these |
| Answer» B. cathode mud | |