PUC Science 2nd PUC Class 12 - Karnataka Board PUC Important Questions for Chemistry

What is the role of CO in the extraction of Iron?

Reduction of metal oxide to metal becomes easier if the metal obtained is in liquid state. Why?

Write the main products when n-butyl chloride is treated with alcoholic KOH.

Write the main products when methyl chloride is treated with AgCN.

What is the role of zinc metal in the extraction of silver ?

Describe the roles of the following: SiO₂ in the extraction of copper from copper matte

Describe the roles of the following: NaCN in froth floatation process

Name the method used for refining of copper metal.

Write the principle behind the froth floatation process. What is the role of collectors in this process?

What is meant by the term “chromatography”?

Outline the principles of refining of metals by the following method:

Vapour phase refining

Arrange the set of compounds in order of increasing boiling points.

Bromomethane, Bromoform, Chloromethane, Dibromomethane.

What are ambident nucleophiles? Explain with an example.

Write the structure of the major organic product in the following reaction:

\[\ce{CH3CH2CH2Cl + NaI ->[acetone][heat]}\]

Write the structure of the major organic product in the following reaction:

\[\ce{C6H5ONa + C2H5Cl ->}\]

What happens when ethyl chloride is treated with aqueous KOH?

How the following conversion can be carried out?

Ethyl chloride to propanoic acid.

C–Cl bond length in chlorobenzene is shorter than C–Cl bond length in CH₃–Cl.

S_N1 reactions are accompanied by racemization in optically active alkyl halides.

What happens when 

(i) PCl₅ is heated ? Write the reactions involved.