Science (English Medium) Class 12 - CBSE Question Bank Solutions

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 ____________.

The vitamins absorbed from intestine along with fats are ____________.

We have three aqueous solutions of NaCl labelled as ‘A’, ‘B’ and ‘C’ with concentrations 0.1 M, 0.01 M and 0.001 M, respectively. The value of van’t Hoff factor for these solutions will be in the order ______.

Sulphur trioxide can be obtained by which of the following:

Which of the following oxides shows electrical properties like metals?

The values of Van’t Hoff factors for KCl, NaCl and K₂SO₄, respectively, are ______.