KMnO4 (acidic/alkaline) is not decolourised by from Chemistry Hy

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

201.

The conditions for aromaticity is :

  • molecule must have clouds of delocalised π electrons

  • molecule must contain (4n + 2) π electrons

  • both (a) and (b)

  • None of the above


202.

Allene (C3H4) contains :

  • one double bond, one triple bond and one single bond

  • one triple and two double bonds

  • two triple and one double bond

  • two double and four single bond


203.

Which of the following is correct number of carbon atom present as the constituent of kerosene oil ?

  • C10 - C16

  • C4 - C6

  • C8 - C16

  • C12 - C18


204.

LPG mainly contains :

  • ethyne

  • butane

  • methane

  • ethane


Advertisement
205.

Alkyl halides react with dialkyl copper reagents to give

  • alkenyl halides

  • alkanes

  • alkyl copper halides

  • alkenes


206.

Amongst the following compounds, the optically active alkane having lowest molecular mass is

  • CH3-CH2-CH2-CH3

  • CH3-CH2-CH(CH3)-CH3

  • CH3-CH2-C≡CH


Advertisement

207.

KMnO4 (acidic/alkaline) is not decolourised by

  • Mohr salt

  • Oxalic acid

  • Benzene

  • Propene


C.

Benzene

The acidic/ alkaline KMnO4 is not decolourised by the aromatic compounds due the delocalisation of π electrons in the nucleus.

Aromatic compounds which have = or ≡ bond in the side chain decolourise acidic/ alkaline KMnO4. Benzene does not decolourise the acidic/ alkaline KMnO4 due to the delocalisation of electrons.

While propene decolourised the alkaline KMnO4 due to the presence of = bond. Ferrous ammonium sulphate and oxalic acid decolourised the KMnO4 in acidic medium.

2KMnO4 + 10FeSO4 + 8H2SO4 → K2SO4 + 2MnSO4 + 5Fe2(SO4)3 + 8H2O

2KMnO4 + 5C2H2O4 + 3H2SO4 → K2SO4 + 2MnSO4 + 10CO2 + 8H2O


Advertisement
208.

When acetylene is passed through dil H2SO4, in presence of HgSOthe compound formed is

  • ether

  • acetaldehyde

  • acetic acid

  • ketone


Advertisement
209.

CH3CH2CH3 400-600°C X + Y

X and Y are

  • hydrogen

  • methane

  • hydrogen

  • ethylene


210.

How many π bonds are present in naphthalene?

  • 4

  • 5

  • 6

  • 7


Advertisement