SOLUTION CHEMISTRY FOR XII C2, XII G2, , XII C, XII G1. The flame colours of metal ions are due to

(a) Frenkel defect (b) Schottky defect(c) Metal deficiency defect (d) Metal excess defect

2. A metal crystallizes in two cubic phases, face centred cubic (fcc) and body centredcubic (bcc) whose unit cell length are 3.5 and 3.0 respectively. Calculate theratio of density of fcc and bcc.(a) 2.123 (b) 1.259 (c) 5.124 (d) 3.134

3. Which of the following figures represents the cross-section of an octahedral site ?

(a) (b) (c) (d)

4. Choose the correct matching sequence from the possibilities given(a) Crystal defect (1) AB AB AB.....type crystal(b) hcp (2) Covalent crystal(c) CsCl (3) Frenkel(d) Diamond (4) Face centered in cube(e) NaCl (5) Body centered in cube(a) a-3, b-1, c-2, d-5, e-4 (b) a-3, b-1, c-5, d-2, e-4(c) a-3, b-5, c-2, d-2, e-4 (d) a-5, b-3, c-4, d-2, e-1

5. A solid has a bcc structure. If the distance of closest approach between the twoatoms is 1.73 . The edge length of the cell is :

(a) 200pm (b) 3 / 2 pm (c) 142.2 pm (d) None of these

6. Choose the incorrect statements(a) Vacancy defects lower the density of the substance(b) Interstitial defects increase the density of the substance(c) Schottky defects, preserve the electrical neutrality of the crystal.(d) Frenkel defects affect the density of the crystal.

7. Pick up the correct statements (a) The ionic crystal of AgCl has Schottky defect(b) The unit cell having crystal parameters, a = b = c, a = b = 90, b = 120 hexago-nal(c) In ionic compounds having Frenkel defect, the ratio r+/r is high(d) The coordination number of Na+ ion in NaCl is 4

8. Select the correct statement (s)(a) In NaCl crystal, each ion has an tetrahedral coordination.(b) The C.N. of an atom in hcp structure is 12.(c) Diamagnetic materials are attracted by the magnetic fields.(d) An octahedral hole is smaller than a tetrahedral hole.

9. As we proceed from NH3 to BiH3, which of the following statements is not correct-(a) The hydrides become more basic(b) The reducing power of the hydrides increases(c) Their stability decreases(d) The ease of replacing hydrogen of the hydrides by other group increases

10. The ionic character of H X is highest in (a) HBr (b) HI (c) HF (d) HCl

11. Which of the following does not form pentoxide (a) As (b) Sb (c) Bi (d) P

12. The molecule having the smallest bond angle is (a) H2O (b) H2S (c) H2Te (d) H2Se

13. Among the trihalides of nitrogen ,the one which is least basic is(a) NF3 (b) NCI3 (c) NBr3 (d) NI3

14. Indicate for the CIF3 molecule, the shape and the type of hybridization (of the Cl-atom)

(a) F sp2 (b) sp3d

(c) sp3d (d)

15. In the nitrogen family the H M H bond angle in the hydrides MH3 graduallybecomes closer to 90 on going from N to Sb. This shows that gradually (a) The basic strength of hydrides increases(b) Almost pure p-orbitals are used for M H bonding(c) The bond energies of M H bond increases(d) The bond pairs of electrons becomes nearer to the central atom

16. In the following reaction

C2H2 2

04 2 4

3/ ,60H O

HgSO H SO CCH CHOx What is X ?

(a) CH3CH2OH (b) CH3-O-CH3 (c) CH3CH2CHO (d)H2C=CHOH

17. The presence of OH groups on adjacent carbon atoms can be detected bythe reaction of the compound with(a) Concentrated H2SO4 (b) Concentration HNO3(c) HIO4 (d) Acid KMnO4

18. Ethylene glycol is treated with HI then product formed is(a) 2 2ICH CH I (b) 2 2CH CH (c) 2 2OHCH CH I ( d )

2CH CHI19. Ethylene glycol on oxidation by 4HIO product formed is

(a) acetaldehyde (b) acetone (c) formaldehyde (d) acrolein

20. Alkaline hydrolysis of oil or fat is known as(a) decarboxylation (b) fermentation(c) decomposition (d) saponification

21. When glycerol is treated with excess HI the product formed is(a) acrolein (b) allyl iodide(c) isopropyl iodide (d) allyl alcohol

22. Ethylidene chloride on treatment with aq. KOH gives(a) CH3CHO (b) CH2OH.CH2OH (c) HCHO (d) CHO. CHO

23. Benzene reacts with CH3COCl in the presence of AlCl3 to give(a) C6H5COCl (b) C6H5Cl (c) C6H5CH3 (d) C6H5COCH3

24. Aldehydes can be prepared from acid chlorides by(a) Clemmensen reduction (b) Wolff-kishner reduction(c) Rosenmund's reduction (d) LiAlH4 reduction.

25. A dihaloalkane on alkaline hydrolysis produces a ketone with formula C3H6O. Thedihaloalkane can be(a) 2,2-Dichloropropane (b) 1,1-Dichloropropane(c) 1,2-Dichloropropane (d) 1,3-Dichloropropane

26. Ozonolysis of an alkene X produce acetaldehyde and acetone then X is(a) 2-butene (b) 2-methyl-2- butene(c) 1-butene (d) 2,3-dimethyl-2-butene

27. When phenol is treated with CHCl3 and NaOH, the product formed is :(a) Benzaldehyde (b) Salicylaldehyde (c) Salicylic acid (d) Benzoicacid

28. IUPAC name of |

3 2 2 3|

CH3

CHO

CH CH C H C H CH CH

(a) 4-methyl hexanal-3 (b) 3-ethyl-2-methyl pentanal(c) 2-ethyl-3-methyl pentanal (d) 4-methyl heptonal

29. When propyne is treated with aqueous sulphuric acid in presence ofMercuric sulphate, the major product is(a) Proponal (b) Propyl Hydrogen Sulphate(c) Propanol (d) Propanone

30. Iso propyl alcohol in presence of Cu at 3000c gives the following(a) Acetaldehyde (b) Acetone(c) Formaldehyde (d) Benzaldehyde

SOLUTION1. (d)

2. (b). = m

3A

n MN a

For fcc centred cubic cell n = 4, a = 3.5

r(fcc) = m

3A

4 MN (3.5)

................. (i)

For bcc latticen = 2, a = 3.0

r(bcc) =m

3A

2 mN (3.0)

................. (ii)

From equations (i) and (ii)

(fcc)

(bcc)

= 42

3

33

(3.5) = 4 3 3 3

2 3.5 3.5 3.5

= 1.259

3. (d)4. (b). Crystal defects are refferred as Frenkel and Schottsky defects.5. (a)6. (b)7. (b)8. (b)9. (a)10. (b). The ionic character is expected to increase as the electronegativity of the halogen increases. Thus due

to the highest electronegativity difference in H and F, the H F bond should be most ionic. But H I bondbeing the weakest gives the hydrogen readily. HI is also the strongest acid because of its least bonddissociation energy. The ionic character thus follows the order HI > HBr > HCl > HF

11. (c). The stability of the highest oxidation states decrease down the group and Bi does not form a pentoxide.Moreover higher oxidation states are more acidic than lower oxidation states.

12. (c). Bond angle decreases in theH2O > H2S > H2Se > H2Te.

13. (a)14. (c). Distorted T-shape; sp3d hybridization15. (b). The hybrids have a pyramidal or tetrahedral shape with a lone pair of electrons in one of the orbitals. The

H M H bond angle is less than the original 10928' tetrahedral bond angle (H N H in NH3 is 10645')because of greater repulsion between lone pair and a bond pair than between two bond pairs of electrons.Because electronegativity of M decreases from N to Bi, the bond pair lie farther away from the central atom,and the lone pair causes greater distortion of bond angle.Thus H P H bond in PH3 is 94, while in AsH3 and SbH3 it is about 91.8 and 91.3 respectively (closerto 90). This suggests that orbtials used for bonding are closer to pure p-orbitals.

16. (d)

C2H22

04 2 4

2/ ,603H O

HgSO H SO CCH CHOCH CHOH

17. (c)18. (b)19. (c)20. (d)21. (c)

22. (a) CH3CH KOH.aq CH3CH

OH2 CH3CHO

23. (d) Electrophilic substitution (Friedel Craft acylation reaction).24. (c)

25. (a)

Cl|

CHCCH|Cl

33 OH/OH 2

OH|

CHCCH|OH

33 OH2 33 CHCCH||O

26. (b)27. (b)28. (c)29. (d)30. (b)