Which of the organic compounds will give red colour in Lassaigne

Subject

Chemistry

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

11.

Which of the following is a wrong statement ? In a given period of the Periodic Table, the s-block element has, in general, a higher value of

  • electronegativity

  • atomic radius

  • ionisation energy

  • electron affinity


12.

What is the H of the reaction?

CH2Cl2 (g) C (g) + 2H (g) + 2Cl (g)

The average bond energies of C-Cl bond and C-H bond are 416 kJ and 325 kJ mol-1 respectively.

  • 1482 kJ

  • 1482 J

  • 1492 kJ

  • 1492 J


13.

Which of the following is a Lewis acid ?

  • OH-

  • H+

  • F-

  • NH3


14.

The bond length of HCl bond is 2.29 x 10-10 m. The percentage ionic character of HCl, if measured dipole moment is 6.226 x 10-30 C- m, is

  • 8%

  • 20%

  • 17%

  • 50%


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15.

The only o  p-directing group which is deactivating in nature is

  • -NH2

  • -OH

  • -X(halogens)

  • -R(alkyl groupd)


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16.

Which of the organic compounds will give red colour in Lassaigne test ?

  • C6H5NH2

  • None of these


B.

If both nitrogen and sulphur are present in a organic compound, they will give red blood colour with Lassaigne test due to the formation of ferric thiocyanate.

Na + C + S + N  NaSCN (sodium thiocyanate)

Fe3+ + 3NaSCN Fe(SCN)3 + 3Na+

                            ferric thiocyanate


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17.

CaC2 and H2O react to produce

  • CH4

  • C2H4

  • C2H2

  • C2H6


18.

The IUPAC name of the following compound is

 

  • 1, 2-dimethyl-2-butenol

  • 3-methylpent-3-en-2-ol

  • 3, 4-dimethyl-2-buten-4-ol

  • None of the above


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19.

Ammonia gas can be dried over

  • CaCl2

  • conc. H2SO4

  • P2O5

  • quick lime


20.

Inorganic benzene is

  • B3N6H3

  • B3N3H6

  • Al3N3H6

  • None of these


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