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

Arrange the following in the order of property indicated for the given set:

HF, HCl, HBr, HI - increasing acid strength.

Give reasons:Ferrimagnetic substances show better magnetism than antiferromagnetic substances.

Complete chemical reactions are:Cl₂ + H₂O →

Complete the following equations:

 KMnO₄ 

Arrange the following in the decreasing order of their reducing character :

HF, HCl, HBr, HI

Based on the type of particles of dispersed phase, give one example each of associated colloid and multimolecular colloid.

Deficiency of which vitamin causes scurvy?

 Cl2 acts as a bleaching agent. 

Out of [CoF₆]^3- and [Co(en)₃]³⁺, which one complex is
(i) paramagnetic
(ii) more stable
(iii) inner orbital complex and
(iv) high spin complex
(Atomic no. of Co = 27) 

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 reason for the following :  
Sulphur in vapour state shows paramagnetic behaviour. 

Define the following term:
Vitamins

Example of ferromagnetic substance is ____________.

Substances which are weakly repelled in magnetic field are known as ____________.

All those atoms or molecules which have an odd number of electrons are

Substances that are strongly attracted by the applied magnetic field and can be permanently magnetized are ____________.

When heated to high temperature, ferromagnetic substance changes to ____________.

Fe₃O₄ is ____________.

Which type of substances would make better permanent magnets?

Assertion: On heating ferromagnetic or ferrimagnetic substances, they become paramagnetic.

Reason: The electrons change their spin on heating.