List of top Chemistry Questions on The Lanthanoids asked in CBSE Class XII

Answer the following questions :

(i) Why is chemistry of actinoids more complicated as compared to lanthanoids ?

(ii) \(E^\circ_{M^{2+}/M}\) values are not regular for first row transition elements (3d series). Why ?

(iii) Identify the following :

(I) Oxoanion of chromium which is stable in acidic medium.

(II) The lanthanoid element that exhibits +4 oxidation state.

(iv) Write the products obtained on heating \(\mathrm{KMnO_4}\).

(v) Predict which of the following ions will be coloured in aqueous solution :

\(\mathrm{Cu^{+}}\), \(\mathrm{Sc^{3+}}\), \(\mathrm{Fe^{2+}}\), \(\mathrm{Ti^{3+}}\), \(\mathrm{Zn^{2+}}\)

(a) Complete and balance the following equations:

(i) \( 2\mathrm{KMnO_4} \xrightarrow{513\ \mathrm{K}} \)

(ii) \( \mathrm{Na_2Cr_2O_7 + 2KCl} \longrightarrow \)

(b) Why is it difficult to separate lanthanoid elements in pure state?

(b) Answer the following questions:

(i) Name a member of the lanthanoid series

(I) which exhibits +4 oxidation state

(II) which exhibits +2 oxidation state.

(ii) Why transition metals act as good catalyst?

(iii) Why Cr has higher melting point than Mn?

Name a member of the lanthanoid series: (I) which exhibits +4 oxidation state; (II) which exhibits +2 oxidation state.