PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions for Chemistry

Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagent.

Tollens’ reagent

An organic compound (A) (molecular formula C₈H₁₆O₂) was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) on dehydration gives but-1-ene. Write equations for the reactions involved.

How will you prepare the given compound from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom.

Methyl benzoate

How will you prepare the given compound from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom.

m-Nitrobenzoic acid

How will you prepare the given compound from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom.

p-Nitrobenzoic acid

How will you prepare the given compound from benzene? You may use any inorganic reagent and any organic reagent having not more than one carbon atom.

Phenylacetic acid

How will you bring about the following conversion in not more than two steps?

Benazaldehyde to α-Hydroxyphenylacetic acid

Complete the synthesis by giving missing starting material, reagent or product.

Comment on the nature of two S−O bonds formed in SO₂ molecule. Are the two S−O bonds in this molecule equal?

How is the presence of SO₂ detected?

How is SO₂ an air pollutant?

Give the structures of A, B and C in the following reactions:

What is the reason for the stability of colloidal sols?

Define the following term:

Zeta potential

Define the following terms: Associated colloids

Give reasons for the following observations:

Brownian movement provides stability to the colloidal solution.

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

CuCN/KCN

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

H₂O

Write the structures of main products when benzene diazonium chloride `(C_6H_5N_2^(+)Cl^-)`reacts with the following reagents:

CH₃CH₂OH

Out of MgCl₂ and AlCl₃, which one is more effective in causing coagulation of negatively charged sol and why?