Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

31.

The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with

  • PCl3

  • PCl5

  • SOCl2 in presence of pyridine

  • dry HCl in the presence of anhydrous ZnCl2


C.

SOCl2 in presence of pyridine

The best method for the conversion of an alcohol into an alkyl chloride is by treating the alcohol with SOCl2 in the presence of pyridine.

R-OH + SOCl2R-Cl + HCl +SO2

The other products being gases escape leaving behind pure alkyl halide.


32.

The compound which forms acetaldehyde when heated with dilute NaOH, is

  • 1,1-dichloroethane

  • 1,1,1-trichloroethane

  • 1-chloroethane

  • 1,2-dichloroethane


A.

1,1-dichloroethane

The compound which forms acetaldehyde when heated with dilute NaOH, is1,1-dichloroethane.


33.

The condensation polymer among the following is

  • rubber

  • protein

  • PVC

  • polyethene


B.

protein

Proteins are the condensation polymers of α-amino acids. Proteins contain peptide -CO-NH bond.


34.

In which of the following, NH3is not used?

  • Tollen's reagent

  • Nessler's reagent

  • Group reagent for the analysis of IV group basic radicals

  • Group reagent for the analysis of III group basic radicals


B.

Nessler's reagent

Potassium tetraiodo mercurate (II),i.e. K2[HgI4] dissolves in KOH solution to give Nessler's reagent. Nesseler's reagent is used to test NH4+ions


35.

The compound which is not formed during the dry distillation of a mixture of calcium formate and calcium acetate is

  • methanal

  • propanal

  • propanone

  • ethanal


B.

propanal

Propanal is not formed during the dry distillation of a mixture of calcium formate and calcium acetate.

(HCOO)2CaDrydistillationHCHO + CaCO3

(CH3COO)2CaCH3COCH3 + CaCO3

(HCOO)2Ca + (CH3COO)2Ca2CH3CHO + 2CaCO3


36.

The dispersed phase and dispersion medium in soap lather are respectively

  • gas and liquid

  • liquid and gas

  • solid and gas

  • solid and liquid


A.

gas and liquid

Soap lather is an example of colloidal system foam, in which the dispersed phase is gas and dispersion medium is liquid.


37.

Cetyltrimethyl ammonium bromide is a popular

  • anionic detergent

  • cationic detergent

  • non-ionic detergent

  • sweetener


B.

cationic detergent

Cetyltrimethyl ammonium bromide which is a germicide, is a popular cationic detergent.


38.

In electrophilic aromatic substitution reaction, the nitro group is meta directing because it

  • decreases electron density at ortho and para positions

  • decreases electron density at meta position

  • increases electron density at meta position

  • ncreases electron density at ortho and para positions


A.

decreases electron density at ortho and para positions

When nitro group is present in the benzene nucleus, it withdraws electrons from ortho andparapositions. Thus, the electron density at the ortho and para positions decreases. Meta position become position of comparatively higher electron density and therefore, electrophilic attack occurs at meta-positions.


39.

Lactose is made of

  • α-D-glucose only

  • α-D-glucose and β-D-glucose

  • α-D-galactose and β-D-glucose

  • β-D-galactose and β-D-glucose


D.

β-D-galactose and β-D-glucose

Lactose (milk sugar) is a disaccharide, obtained by the condensation of one molecule of β-D-galactopyranose and one molecule of β-D-glucopyranose.


40.

Amine that cannot be prepared by Gabrielphthalimide synthesis is

  • aniline

  • benzylamine

  • methylamine

  • iso-butylamine


A.

aniline

Only aliphatic primary amines can be prepared by Gabriel synthesis. Aniline cannot be prepared by this method because aryl halides (C6H5Cl or C6H5Br) do not undergo nucleophilic substitution with potassium phthalimide under ordinary conditions to give N-phenyl phthalimide(i.e., cleavage of C-X bond in haloarenes is quite difficult).

RX = aliphatic halide