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

The elements of 3d transition series are given as: Sc Ti V Cr Mn Fe Co

Answer the following: Which element is a strong oxidising agent in +3 oxidation state and why?

Why do the transition elements have higher enthalpies of atomisation?

In 3d series (Sc to Zn), which element has the lowest enthalpy of atomisation and why?

Give reasons for the following observations:

Physisorption decreases with increase in temperature.

How would you account for the following: Transition metals form complex compounds.

Write the names and structures of the monomers of the following polymers: Buna-N

Differentiate between adsorbtion and absorption.

Give reasons:

Transition metals show variable oxidation states.

Write the name of two monosaccharides obtained on hydrolysis of lactose sugar.

What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 1/3^rd of tetrahedral voids?

What are the transition elements? Write two characteristics of the transition elements.

How would you account for the following : Transition metals form coloured compounds

Write the product obtained when D-glucose reacts with H₂N − OH.

Define the following term: Primitive unit cells

Account for the following:

Cu⁺ ion is unstable in aqueous solution.

From the given data of E⁰ values, answer the following questions :

(1) Why is `E_(((Cu^(2+))/(Cu)))` value exceptionally positive

(2) Why is `E_(((Mn^(2+))/(Mn)))` value is highly negative as compared to other elements

(3) Which is the stronger reducing agents Cr²⁺ or Fe²⁺ ? Give Reason.

What is the effect of temperature on chemisorption ?

How will you distinguish between the following pair of terms?

Crystal lattice and unit cell

Account for the following:

Zn is not considered as a transition element.

Account for the following:

E° value for the Mn³⁺/Mn²⁺ couple is much more positive than that for Cr³⁺/Cr²⁺.