Noly Runc, le (d) ether, amine, ketone 12. Select the acid with the highest Ka (i.е., lowest pKa). ОН "ОН (а) Н3СОНФ) Сін он (d) с

Select the acid with the highest Ka (i.e., lowest pK_a )

Which properties of element depend on the electronic configuration of atoms and which do not (b) Why the chemical properties of a group are similar Why do they not have identical properties (c ) Account for the great chemical similarity of the lanthanoid elements (Z =57 to 71) (d) Select the largest species in each group (i) Ti^(2),Ti^(+3) (ii) F^(Θ),Ne,Na^(o+) (e) Select the species with the largest IE in each group (i ) na,K,Rb (ii) F,Ne,Na (f) Which ion has the smallest radius Li^(o+),Na^(o+),K^(o+) Be^(+2), Mg^(+2) (g) Select among the element that has the lowest and highest IE K, Ca, Se, B, Kr , (h) The ionic radii of S^(2-) and Te^(2-) are and 220 pm respectively Predict the ionic radius of Se^(2-) and for p^(3-) (i) In the ionic compound KF the K^(o+) and F^(o+) have practically identical radii, about 134 pm each. Predict the relative atomic radii of 1 K and F .

Select the species which is best described to the right (a) CI_(2),Br_(2),I_(2) (has the lowest boiing point) (b) CI,Ar,K (has the smallest IE ) (c ) CH_(4), NH_(3),HF (has the highest boiling point) (d) CO_(2),NH_(3),CO (has zero dipole moment) (e) HOI,HOBr,HOCI (is the weakest acid) .

The group state electronic configuration of some elements, P,Q,R,S and T (these symbols represent the some of the known elements given in the periodic table) are as follows. ltbr. (P) :1s^(2)2s^(2)2p^(6)3s^(2)3p^(2) (Q) :1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)4s^(1) (R) :1s^(2)2s^(2)2p^(6)3s^(2)3p^(1) (S) :1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(5)4s^(1) (T) :1s^(2)2s^(2)2p^(^)3s^(2)3p^(6)3s^(10)4s^(2)4p^(6) Match the electronic configurations of the elements with the properties given below and select the correct sequence by choosing the correct codes given. (i) Element forms a cation which is isoelectronic with P^(3-) . (ii) Element which in its compounds can show a maximum oxidation state of +6 and that is coloured too. (iii) Element has largest atomic radius and highest first ionisation energy in the respective period. (iv) Element which has intermediate value of electronegativity and its oxide forms salts with strong acids and bases.

H_2SO acts as (i). An acid. (ii) An oxidising agent A dehydrating agent Select equations from rthe following which explain each type (a) 5H_2SO_4("conc")+4Znto4Zn^(2+)+H_2S+4SO_4^(2-)+4H_2O (b) H_2SO_4("dil")+ZntoZn^(2+)+H_2+SO_4^(2-) (c) C_(6)H_(12)O_(6) overset(H_(2)SO_(4)("conc"))to6C +6H_(2)O (d) H_(2)SO_(4)("dil")+ZnCO_(3) rarr Zn^(2+) +CO_(2)+SO_(4)^(2-)+H_(2)O .

H_2SO acts as (i). An acid. (ii) An oxidising agent A dehydrating agent Select equations from rthe following which explain each type (a) 5H_2SO_4("conc")+4Znto4Zn^(2+)+H_2S+4SO_4^(2-)+4H_2O (b) H_2SO_4("dil")+ZntoZn^(2+)+H_2+SO_4^(2-) (c) C_(6)H_(12)O_(6) overset(H_(2)SO_(4)("conc"))to6C +6H_(2)O (d) H_(2)SO_(4)("dil")+ZnCO_(3) rarr Zn^(2+) +CO_(2)+SO_(4)^(2-)+H_(2)O .

Read the passage given below and answer the following questions: Reduction of carboxylic acids and their derivatives plays an important role in organic synthesis, in both laboratory and industrial processes. Traditionally, the reduction is performed using stochiometric amounts of hydride reagents, generating stochiometric amounts of waste. A much more attractive, atom-economical approach is a catalytic reaction using H_2 , however, hydrogenation of carboxylic acid derivatives under mild conditions is a very challenging task, with amides presenting the highest challenge among all classes of carbonyl compounds. Very few examples of the important hydrogenation of amides to amines, in which the C-O bond is cleaved with the liberation of water (Scheme 1), were reported. C-O cleavage of amides can also be affected with silanes as reducing agents. We have now prepared the new, dearomatized, bipyridine-based pincer complex 3, catalyst 3(Here refered as Cat. 3). Remarkably, it efficiently catalyzes the selective hydrogenation of amides to form amines and alcohols (eq 1). The reaction proceeds under mild pressure and neutral conditions, with no additives being required. Since the reaction proceeds well under anhydrous conditions, hydrolytic cleavage of the amide is not involved in this process. (Balaraman, E., Gnanaprakasam, B., Shimon, L. J., & Milstein, D. (2010). Direct hydrogenation of amides to alcohols and amines under mild conditions. Journal of the American Chemical Society, 132(47), 16756-16758.) In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage. Assertion: The use of catalyst 3 is an efficient method of preparation of primary amines Reason: Use of catalyst 3 is a step down reaction.

Read the passage given below and answer the following questions: Reduction of carboxylic acids and their derivatives plays an important role in organic synthesis, in both laboratory and industrial processes. Traditionally, the reduction is performed using stochiometric amounts of hydride reagents, generating stochiometric amounts of waste. A much more attractive, atom-economical approach is a catalytic reaction using H_2 , however, hydrogenation of carboxylic acid derivatives under mild conditions is a very challenging task, with amides presenting the highest challenge among all classes of carbonyl compounds. Very few examples of the important hydrogenation of amides to amines, in which the C-O bond is cleaved with the liberation of water (Scheme 1), were reported. C-O cleavage of amides can also be affected with silanes as reducing agents. We have now prepared the new, dearomatized, bipyridine-based pincer complex 3, catalyst 3(Here refered as Cat. 3). Remarkably, it efficiently catalyzes the selective hydrogenation of amides to form amines and alcohols (eq 1). The reaction proceeds under mild pressure and neutral conditions, with no additives being required. Since the reaction proceeds well under anhydrous conditions, hydrolytic cleavage of the amide is not involved in this process. (Balaraman, E., Gnanaprakasam, B., Shimon, L. J., & Milstein, D. (2010). Direct hydrogenation of amides to alcohols and amines under mild conditions. Journal of the American Chemical Society, 132(47), 16756-16758.) In the following questions, a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices on the basis of the above passage. Assertion: N-methyl ethanamide on reaction with catalyst 3 will yield ethanol and methanamine. Reason: Use of Catalyst 3 brings about cleavage of C-N bond of amides