iv group1.pdf

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Although stoichiometry similarities exists between the compounds of carbon and those of the

remaining elements of group IV B, there is no structural or chemical similarity between them. Ex : CO2

is gas SiO2is solid. Reaction of the compounds of silicon and the lower elements of group donot give

products analogous to those for carbon . For example the dehydration of alcohols gives alkene but the

dehydration of silanols give different products accompained by condensation.In carbon multiple bonds involve overlap of the p p- variety mulitple bonding for silicon and

germanium usually arise fromp d- component especially in bonds to O and N. It is important to note

that this does not usually lead to conjugation as is so prevalent for carbon. Thep d- bonding character

decreases with increase the atomic size down the group. Q. No. 1 to 7

1. Among trisylylamine (H3Si)

3N and trimethyl amine (CH

3)

3N

1) (H3Si)

3N and (CH

3)

3N both are pyramidal in shape and equally basic.

2) (H3Si)

3N and (CH

3)

3N both are pyramidal in shape but (H

3Si)

3N is more basic than (CH

3)

3N

3) (H3Si)

3N is planar while (CH

3)

3N is pyramidal and (H

3Si)

3N is more basic than (CH

3)

3N

4) (H3Si)

3N is planar while (CH

3)

3N is pyramidal and (H

3Si)

3N is less basic than (CH

3)

3N

2. Among (H3Si)

3P and (H

3Si)

3N

1) Both are pyramidal in which P and N are involved in sp3hybridisation.

2) Both are planar in which P and N are involved in sp2hybridisation.

3) (H3Si)

3P is planar while (H

3Si)

3N is pyramidal where P is involved in sp2and N is involved in sp3hybridisation.

4) (H3Si)

3P is pyramidal with P is involved in sp3hybridisation while (H

3Si)

3N is planar with N is involved in

sp2hybridisation.

3. Among H3Si NCO and H

3C NCO

1) Both are linear 2) Both are angular

3) H3Si NCO is linear while H

3CNCO is angular 4) H

3SiNCO is angular while H

3CNCO is linear

4. Compared to dialkyl ethers, the disilyl ethers (R3Si)2O have large bond angles at oxygen (140 - 1800). This iddue to

1) Steric effect of the bigger disilyl groups than dialkyl groups at oxygen.

2) Overlap between filled oxygenp orbitals and empty silicon d orbitals.

3) Both steric effect of silyl groups and overlap of filled oxygenp orbitals and empty silicon d orbitals.

4) The differencef in the nature of the elements.

5. Compared to carbon analogs silanols such as (CH3)

3SiOH are

1) stronger protonic acids 2) weaker protonic acids

3) equally stronger pronic acids 4) cannot be predicted

6. When silanols are condensed by dehydration, silicones are formed. When three moles of R2Si (OH)2isaccomopained by condensation giving (R

2SiO)

3and (R

2(OH)SiO Si OSi (OH) R

2

1) The (R2SiO)

3is linear silicone while R

2(OH)Si OSi (OH)R

2is cyclic primer..

2) The (R2SiO)

3is a cyclic primer while R

2(OH)Si OSi (OH)R

2is linear silicone.

3) Both are cyclic silicones 4) Both are linear silicones

7. Which of the following do not containp d- multiple bonding.

1) (H3Si)

3N 2) (H

3Si)

3P 3) H

2Si NCO 4) (R

3Si)

2O

8. Which of the following statements is not true?

1) SnCl2is ionic solid 2) SnCl

2is reducing in nature

3) SnCl4

is reducing in nature 4) SnCl4

is covalent liquid

9. The correct order of decreasing ionic character of lead dihalides is

1) pbF2> pbCl

2> pbBr

2> pbI

22) pbF

2> pbBr

2> pbCl

2> pbI

2

3) pbF2> pbI

2> pbCl

2> pbBr

24) pbCl

2> pbBr

2> pbF

2> pbI

2


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10. A solid element (symbol y) conducts electricity and forms two chlorides YCln(a colourless volatile liquid)

and YCln-2

(a colourless solid). To which one of the following groups of the periodic table does y belong

1) 13 2) 14 3) 15 4) 16

11. The raw materials for the manufacture of flint glass are

1) Gypsum, sand and Na2CO

32) Litharge, sand and K

2CO

3

3) Gypsum, sand and K2CO3 4) Sand, Na2CO3and CaCO312. What is not true about silicon element?

1) silicon exists in three isotopic forms 2) Elemental silicon has a structure similar to diamond

3) Most common and abundant isotope of silicon is Si-30

4) High purify silicon is used as semi-conductor in electronic devices

13. Which of the following chemical process does not produce silicon

1) SiO2+ C 2) SiC + SiO

2 3) SiH

4

675K 4) SiCl4

Heat

14. What is false about glass?

1) Glass is a super cooled liquid

2) the composition of flint glass is approximately K2O.pbO.6SiO

2

3) Pyrax glass is obtained by the addition of cerium oxide to glass mix

4) Addition of CdS to glass mix imparts lemon yellow colour to glass

15. Solid CO2is produced as white snow by

1) cooling the gas below its inversion temperature

2) cooling the gas below its Boyles temperature

3) expanding the gas at high temperature

4) the adiabatic expansion of the compressed gas by allowing it to escape through the orifice in the container

16. What is correct about chlorides of tin

1) SnCl2is solid while SnCl

4is liquid 2) SnCl

2is liquid while SnCl

4is solid

3) SnCl2and SnCl

4are both liquids 4) SnCl

2and SnCl

4are both solids

17. The inter layer distance in graphite is

1) very small, the layers being tightly packed 2) many times larger than the covalent radius of carbon

3) more than twice the covalent radius of carbon 4) the same as the covalent radius of carbon

18. Which of the following statement is correct

1) An aqueous solution of sodium carbonate is neither acidic nor basic

2) An aqueous solution of sodium carbonate is alkaline because being a base, the carbonate ion picks up

the hydrogen ion from water releasing a hydroxide ion, making the solution alkaline

CO3

2 -+H2O

HCO3

- +OH -

3) An aqueous solution of sodium carbonate is acidic because, being very electronegative, the sodium ion

picks up the hydroxide ion from water to release a hydrogen ion making the solution acidic

2Na++H2O

2NaOH+2H+

4) An aqueous solution of sodium carbonate is acidic because the carbonate ion reacts with water to form

carbonic acid

CO3

2 -+2H2O

H

2CO

3+2OH-

19. Carbon shows strong catenation while silicon shows little or no catenation because

1) Silicon is a metalloid and carbon is a non metal

2) Silicon forms ionic compounds whereas carbon forms covalent compounds3) The Si-Si bond is stronger than the C-C bond

4) The C-C bond is stronger than Si-Si bond


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20. Select correct statement

1) Cyanamide ion -22CN is iso-electronic with CO2and has the same linear structure

2) Mg2C

3reacts with water to form propyne

3) CaC2has NaCl type of lattice

4) all are correct statements

21. Silicons are

1) Synthetic polymers containing repeated R2SiO units

2) Silicates with common SiO4unit

3) Ketones with silyl group (SiH3) similar to alkyl, (SiH

3)

2CO

4) Zircon (meso silicates)

22. Formula of the following silicate anion is

1) SiO4

4 - 2) Si2O

7

6 - 3) Si2O

8

6 - 4) Si3O

96 -

23. The minerals having silicate chains are collectively called

1) olivine 2) zircon 3) pyroxene 4) natrolite

24. Which is/are true statements

1) diamond is unaffected by conc acids but graphite reacts with conc.HNO3forming mellitic acid,

C6(COOH)

6.

2) CO is toxic because it forms complex with haemoglobin in the blood

3) C3O

2, carbon sub oxide, is a foul smelling gas

4) All are true statements

25. Which is the true statement about glass

1) glass is a supper coold liquid and is a solid solution

2) the glass would be water soluble if only Na2O or K

2O were used

3) glass of high refractive index has PbO and opal glass has CaF2

4) all are true statements


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1) 4 2) 4 3) 3 4) 3 5) 1 6) 2 7) 2 8) 3 9) 1 10) 2

11) 2 12) 3 13) 4 14) 3 15) 4 16) 1 17) 2 18) 19) 4 20) 4

21) 1 22) 2 23) 3 24) 4 25) 4

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