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

Give reasons for the following statement:

Transition metals and most of their compounds show paramagnetic behaviour.

Give reasons for the following statement:

Zn, Cd, and Hg are soft metals.

Give reason for the following statement:

[Ti(H₂O)]³⁺ is coloured while [Sc(H₂O)₆]³⁺ is colourless.

Give reason for the following statement:

Physical and chemical properties of the 4d and 5d series of the transition elements are quite similar to expected.

An organic compound (A) with molecular formula C₃H₇NO on heating with Br₂ and KOH forms a compound (B). Compound (B) on heating with CHCl₃ and alcoholic KOH produces a foul-smelling compound (C) and on reacting with C₆H₅SO₂Cl forms a compound (D) which is soluble in alkali. Write the structure of (A), (B), (C) and (D).

Account for the following:

Transition metals form alloys.

Why Zn, Cd and Hg are not called transition metals?

How is the variability in oxidation states of transition metals different from that of p-block elements?

The oxidation state of Fe in [Fe(CO)₅] is ______.

Which of the following characteristics of transition metals is associated with their catalytic activity?

Do the following conversions in not more than two steps:

\[\begin{array}{cc}
\ce{CH3CN to CH3 - C - CH3}\\
\phantom{...........}||\\
\phantom{...........}\ce{O}
\end{array}\]

Do the following conversions in not more than two steps:

Account for the following:

Sc³⁺ is colourless whereas Ti³⁺ is coloured in an aqueous solution.

Account for the following:

Ce⁴⁺ is a strong oxidising agent.

Assertion (A): Transition metals have high enthalpy of atomisation.

Reason (R): Greater number of unpaired electrons in transition metals results in weak metallic bonding.

Which one among the following metals of the 3d series has the lowest melting point?

Which of the following transition metals shows +1 and +2 oxidation states?

Assertion (A): Transition metals show their highest oxidation state with oxygen.

Reason (R): The ability of oxygen to form multiple bonds to metals.

Which property of transition metals enables them to behave as catalysts?

Why is the C-O bond length in phenols less than that in methanol?