Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Chemistry

Out of o-nitrophenol and o-cresol which is more acidic?

Assertion: o-Nitrophenol is less soluble in water than the m- and p-isomers.

Reason: m- and p- Nitrophenols exist as associated molecules.

Cannizaro’s reaction is not given by ______.

Which product is formed when the compound  is treated with concentrated aqueous \[\ce{KOH}\] solution?

Compounds A and C in the following reaction are:

\[\ce{CH3CHO ->[(i) CH3MgBr][(ii) H2O] (A) ->[H2SO4, Δ] (B) ->[Hydroboration oxidation] (C)}\]

Which of the following compounds do not undergo aldol condensation?

(i) \[\ce{CH3 - CHO}\]

(ii)  

(iii)  \[\begin{array}{cc}
\phantom{}\ce{O}\\
\phantom{}||\\
\ce{CH3 - C - CH3}
\end{array}\]

(iv) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]

Which of the following conversions can be carried out by Clemmensen Reduction?

(i) Benzaldehyde into benzyl alcohol

(ii) Cyclohexanone into cyclohexane

(iii) Benzoyl chloride into benzaldehyde

(iv) Benzophenone into diphenyl methane

Why is there a large difference in the boiling points of butanal and butan-1-ol?

What product will be formed on reaction of propanal with 2-methylpropanal in the presence of \[\ce{NaOH}\]? What products will be formed? Write the name of the reaction also.

Compound ‘A’ was prepared by oxidation of compound ‘B’ with alkaline \[\ce{KMnO4}\]. Compound ‘A’ on reduction with lithium aluminium hydride gets converted back to compound ‘B’. When compound ‘A’ is heated with compound B in the presence of \[\ce{H2SO4}\] it produces fruity smell of compound C to which family the compounds ‘A’, ‘B’ and ‘C’ belong to?

Why are carboxylic acids more acidic than alcohols or phenols although all of them have hydrogen atom attached to a oxygen atom \[\ce{(-O-H)}\]?

Assertion: The α-hydrogen atom in carbonyl compounds is less acidic.

Reason: The anion formed after the loss of α-hydrogen atom is resonance stabilised.

Assertion: Aromatic aldehydes and formaldehyde undergo Cannizaro reaction.

Reason: Aromatic aldehydes are almost as reactive as formaldehyde.

When liquid ‘A’ is treated with a freshly prepared ammoniacal silver nitrate solution, it gives bright silver mirror. The liquid forms a white crystalline solid on treatment with sodium hydrogensulphite. Liquid ‘B’ also forms a white crystalline solid with sodium hydrogensulphite but it does not give test with ammoniacal silver nitrate. Which of the two liquids is aldehyde? Write the chemical equations of these reactions also.

A primary amine, \[\ce{RNH2}\] can be reacted with \[\ce{CH3-X}\] to get secondary amine, \[\ce{R-NHCH3}\] but the only disadvantage is that 3° amine and quaternary ammonium salts are also obtained as side products. Can you suggest a method where \[\ce{RNH2}\] forms only 2° amine?

Assertion: Acetanilide is less basic than aniline.

Reason: Acetylation of aniline results in decrease of electron density on nitrogen.

Identify the type of polymer.

—A—B—B—A—A—A—B—A—

Which of the following chemicals can be added for sweetening of food items at cooking temperature and does not provide calories?

Which of the following will not enhance nutritional value of food?

Which of the following are not used as food preservatives?

(i) Table salt

(ii) Sodium hydrogencarbonate

(iii) Cane sugar

(iv) Benzoic acid