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

How is SO₂ an air pollutant?

Define the term abnormal molar mass.

Write the reactions involved Decarboxylation reaction

How will you convert the following in not more than two steps:

Benzoic acid to Benzaldehyde

How will you convert the following in not more than two steps:

Acetophenone to Benzoic acid

Give reasons for the following

Elevation of the boiling point of 1 M KCl solution is nearly double than that of 1 M sugar solution.

Account for the following:

PCl₅ is more covalent than PCl₃.

Account for the following :

SnCl₄ is more covalent than SnCl₂.

Deficiency of which vitamin causes scurvy?

 Predict whether van’t Hoff factor, (i) is less than one or greater than one in the following: 
CH₃COOH dissolved in water 

An aromatic compound 'A' on heating with Br₂ and KOH forms a compound 'B' of molecular formula C₆H₇N which on reacting with CHCl₃ and alcoholic KOH produces a foul-smelling compound 'C'. Write the structures and IUPAC names of compounds A, B, and C.

Give a reason for the following : 
N-N bond is weaker than the P-P bond.

Answer the following question.
Write a chemical reaction to test sulphur dioxide gas. write a chemical equation involved.

Define the following term:
Vitamins

Which substance has conductivity in the range 10^-20 to 10^-10 ohm^-1 m^-1?

The property of a substance to offer no resistance to the flow of electricity at a particular temperature is known as ____________.

At what temperature range do most of the metals become superconductors?

Which of the following solids is not an electrical conductor?

1. Mg (s)
2. TiO (s)
3. I₂ (s)
4. H₂O (s)

Graphite is a good conductor of electricity due to the presence of ______.

The van’t Hoff factor (i) accounts for ____________.