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

Out of Mn³⁺ and Cr³⁺, which is more paramagnetic and why ?

(Atomic nos. : Mn = 25, Cr = 24)

Why is adsorption always exothermic?

Why does NO₂ dimerise?

Give the significance of a ‘lattice point’.

Name the parameters that characterize a unit cell.

Which of the following lattices has the highest packing efficiency (i) simple cubic (ii) body-centred cubic and (iii) hexagonal close-packed lattice?

What is meant by the term ‘coordination number’?

How would you determine the standard electrode potential of the system Mg²⁺ | Mg?

Consult the table of standard electrode potentials and suggest three substances that can oxidise ferrous ions under suitable conditions.

Calculate the standard cell potential of a galvanic cell in which the following reaction takes place:

\[\ce{2Cr_{(s)} + 3Cd{^{2+}_{(aq)}} -> 2Cr{^{3+}_{(aq)}} + 3Cd_{(s)}}\]

Calculate the Δ_rG° and equilibrium constant of the reaction.

Write any two characteristics of chemisorption.

Why are powdered substances more effective adsorbents than their crystalline forms?

Distinguish between the meaning of the terms adsorption and absorption. Give one example of.

What is the difference between physisorption and chemisorption?

Give reason why a finely divided substance is more effective as an adsorbent.

What are the factors which influence the adsorption of a gas on a solid?

Discuss the effect of temperature on the adsorption of gases on solids.

Which of the 3d series of the transition metals exhibits the largest number of oxidation states and why?

The \[\ce{E^{\circ}_{(M^{2+}/M)}}\] value for copper is positive (+0.34 V). What is possible reason for this? (Hint: consider its high Δ_aH° and low Δ_hydH°)