Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions

Arrange following complex ions in increasing order of crystal field splitting energy (∆_O):

\[\ce{[Cr(Cl)6]^{3-}, [Cr(CN)6]^{3-}, [Cr(NH3)6]^{3+}}\].

\[\ce{CuSO4 . 5H2O}\] is blue in colour while \[\ce{CuSO4}\] is colourless. Why?

Match the complex ions given in Column I with the hybridisation and number of unpaired electrons given in Column II and assign the correct code:

Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following:

\[\ce{[CoF6]^{3-}, [Co(H2O)6]^{2+}, [Co(Cn)6]^{3-}}\]

Using crystal field theory, draw energy level diagram, write electronic configuration of the central metal atom/ion and determine the magnetic moment value in the following:

\[\ce{[FeF6]^{3-}, [Fe(H2O)6]^{2+}, [Fe(CN)6]^{4-}}\]

Why are different colours observed in octahedral and tetrahedral complexes for the same metal and same ligands?

Toluene reacts with a halogen in the presence of iron (III) chloride giving ortho and para halo compounds. The reaction is ______.

Assertion: In monohaloarenes, further electrophilic substitution occurs at ortho and para positions.

Reason: Halogen atom is a ring deactivator.

Phenol is less acidic than ______.

Phenol can be distinguished from ethanol by the reactions with:

(i) \[\ce{Br2/water}\]

(ii) \[\ce{Na}\]

(iii) Neutral \[\ce{FeCl3}\]

(iv) All the above

Write the IUPAC name of the following compound.

\[\begin{array}{cc}
\phantom{.}\ce{CH3 - CH - CH - CH - CH - CH3}\phantom{}\\
\phantom{......}|\phantom{......}|\phantom{......}|\phantom{.....}|\phantom{........}\\
\phantom{...}\ce{CH3}\phantom{...}\ce{OH}\phantom{...}\ce{C2H5}\phantom{.}\ce{OH}\phantom{...}\end{array}\]

What is denatured alcohol?

Out of 2-chloroethanol and ethanol which is more acidic and why?

Suggest a reagent for conversion of ethanol to ethanal.

Suggest a reagent for conversion of ethanol to ethanoic acid.

Arrange the following compounds in increasing order of acidity and give a suitable explanation.

Phenol, o-nitrophenol, o-cresol

Name the enzymes and write the reactions involved in the preparation of ethanol from sucrose by fermentation.

Dipole moment of phenol is smaller than that of methanol. Why?

The carbon-oxygen bond in phenol is slightly stronger than that in methanol. Why?

Arrange water, ethanol and phenol in increasing order of acidity and give reason for your answer.