Q20 of 26 Page 1

(a) How would you account for the following:

(i) Highest fluoride of Mn is MnF4 whereas the highest oxide is Mn2O7.


(ii) Transition metals and their compounds show catalytic properties.


(b) Complete the following equation:


3 MnO42- + 4 →


(a) (i)


As it can be seen from the above two structures, oxygen is able to form multiple bonds while fluorine does not. Therefore, Highest fluoride of Mn is MnF4 only whereas the highest oxide is Mn2O7.


(ii) Transition metals have incomplete d-orbitals. So they are able to form multiple oxidation states when compared to other metals. Hence, they are effective catalysts.


(b) 3 MnVIO42- + 4H+ → 2MnVIIO4- + MnIVO2 + 2H2O


Manganese (VI) is unstable when compared to manganese (VII) and manganese (IV) in acidic solution. This reaction is called as disproportionation reaction.


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18

(a) Why are alkyl halides insoluble in water?

(b) Why is Butan-1-ol optically inactive but Butan-2-ol is optically active?


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


 19

How do you convert the following:

(i) Benzoic acid to Benzaldehyde


(ii) Ethyne to Ethanal


(iii) Acetic acid to Methane


OR


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(i) Stephen reaction


(ii) Wolff-Kishner reaction


(iii) Etard reaction


 21

Predict the products of the following reactions:

(i)


(ii)


(iii)


22

An element X (molar mass = 60 g mol-1) has a density of 6.23 g cm-3. Identify the type of cubic unit cell, if the edge length of the unit cell is 4× 10-8 cm.