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

How will you obtain monobromobenzene from aniline?

How can you obtain iodoethane from ethanol when no other iodine-containing reagent except NaI is available in the laboratory?

Match the compounds given in Column I with the effects given in Column II.

Assertion: It is difficult to replace chlorine by –OH in chlorobenzene in comparison to that in chloroethane.

Reason: Chlorine-carbon \[\ce{(C - Cl)}\] bond in chlorobenzene has a partial double bond character due to resonance.

Some halogen containing compounds are useful in daily life. Some compounds of this class are responsible for exposure of flora and fauna to more and more of UV light which causes destruction to a great extent. Name the class of these halocompounds. In your opinion, what should be done to minimise harmful effects of these compounds.

The reagent which does not react with both, acetone and benzaldehyde.

Which is the most suitable reagent for the following conversion?

\[\begin{array}{cc}
\phantom{....................}\ce{O}\phantom{.....................................}\ce{O}\phantom{.}\\
\phantom{....................}||\phantom{......................................}||\phantom{.}\\
\phantom{}\ce{CH3 - CH = CH - CH2 - C - CH3 -> CH3 - CH = CH - CH2 - C - OH}\phantom{.}
\end{array}\]

Through which of the following reactions number of carbon atoms can be increased in the chain?

(i) Grignard reaction

(ii) Cannizaro’s reaction

(iii) Aldol condensation

(iv) HVZ reaction

Match the reactions given in Column I with the suitable reagents given in Column II.

Assertion: Aldehydes and ketones, both react with Tollen’s reagent to form silver mirror.

Reason: Both, aldehydes and ketones contain a carbonyl group.

Arenium ion involved in the bromination of aniline is:

(i)

(ii)

(iii)

(iv)

Why is benzene diazonium chloride not stored and is used immediately after its preparation?

Why does acetylation of –NH₂ group of aniline reduce its activating effect?

Predict the product of reaction of aniline with bromine in non-polar solvent such as \[\ce{CS2}\].

Why is aniline soluble in aqueous HCl?

How will you carry out the following conversions?

toluene `->` p-toluidine

How will you carry out the following conversions?

p-toluidine diazonium chloride `→` p-toluic acid

Match the compounds given in Column I with the items given in Column II.

A colourless substance ‘A’ \[\ce{(C6H7N)}\] is sparingly soluble in water and gives a water soluble compound ‘B’ on treating with mineral acid. On reacting with \[\ce{CHCl3}\] and alcoholic potash ‘A’ produces an obnoxious smell due to the formation of compound ‘C’. Reaction of ‘A’ with benzenesulphonyl chloride gives compound ‘D’ which is soluble in alkali. With \[\ce{NaNO2}\] and \[\ce{HCl}\], ‘A’ forms compound ‘E’ which reacts with phenol in alkaline medium to give an orange dye ‘F’. Identify compounds ‘A’ to ‘F’.

Predict the reagent or the product in the following reaction sequence.