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

Non-stoichiometric cuprous oxide, Cu₂O can be prepared in laboratory. In this oxide, copper to oxygen ratio is slightly less than 2 : 1. Can you account for the fact that this substance is a p-type semiconductor?

Classify each of the following as being either a p-type or a n-type semiconductor:

1. Ge doped with In 
2. B doped with Si

Explain the following with suitable examples:

12-16 group compounds

What modification can you suggest in the Hardy-Schulze law?

Explain what is observed when a beam of light is passed through a colloidal sol.

Explain what is observed when an electrolyte NaCl is added to hydrated ferric oxide sol.

Explain what is observed when an electric current is passed through a colloidal sol?

Explain the term Electrophoresis

Explain the terms Coagulation

Explain the terms Dialysis 

Explain the term Tyndall effect.

What happens when sulphur dioxide is passed through an aqueous solution of Fe(III) salt?

What type of semiconductor is obtained when silicon is doped with boron? 

Although phenoxide ion has more number of resonating structures than carboxylate ion, carboxylic acid is a stronger acid than phenol. Give two reasons.

Give reasons for the following observations: Addition of alum purifies the water

Write the conditions to maximize the yield of H₂SO₄ by contact process.

Why pKa of F-CH₂-COOH is lower than that of Cl−CH₂−COOH?

Distinguish between the following : Benzoic acid and methyl benzoate

What are emulsions?

What are the different types of emulsions? Give one example of each type.