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

Nitrogen exists as diatomic molecule and phosphorus as P₄. Why?

Write main differences between the properties of white phosphorus and red phosphorus.

Why does nitrogen show catenation properties less than phosphorus?

Arrange the following compound groups in the increasing order of their property indicated :

p-nitrophenol, ethanol, phenol (acidic character)

Arrange the following compound groups in the increasing order of their property indicated :

Propanol, Propane, Propanal (boiling point)

For a reaction R ---> P, half-life (t_1/2) is observed to be independent of the initial concentration of reactants. What is the order of reaction?

Define the following : Narrow spectrum antibiotics

Based on the nature of intermolecular forces, classify the following solids:

Sodium sulphate, Hydrogen

Why does copper obtained in the extraction from copper pyrites have a blistered appearance?

Arrange the following in the increasing order of property mentioned:

NH₃, PH₃, AsH₃, SbH₃, BiH₃ (Base strength)

Among the hydrides of Group-15 elements, which have the lowest boiling point?

Among the hydrides of Group-15 elements, which have the maximum basic character?

Among the hydrides of Group-15 elements, which have the highest bond angle?

Among the hydrides of Group-15 elements, which have the maximum reducing character?

Give reasons H₃PO₃ undergoes disproportionation reaction but H₃PO₄ does not.

Give reasons When Cl₂ reacts with the excess of F₂, ClF₃ is formed and not FCl₃.

Although chlorine is an electron withdrawing group, yet it is ortho-, para- directing in electrophilic aromatic substitution reactions. Why?

What is 'copper matte' ?

Account for the following :

Reducing character decreases from SO2 to TeO₂

Account for the following :

BiH₃ is the strongest reducing agent amongst all the hydrides of group 15.