All India Engineering / Architecture Entrance Examination (AIEEE)

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AIEEE 2007 Chemistry

Q. 32. The IUPAC name of is

1. 1,1–diethyl–2,2–dimethylpentane
2. 4,4–dimethyl–5,5–diethylpentane
3. 5,5–diethyl–4,4–dimethylpentane
4. 3–ethyl–4,4–dimethylheptane

Sol:

IUPAC name of the given compound is: 3–ethyl–4,4–dimethyl heptane.
Correct choice: (4)

Q. 33. Which of the following species exhibits the diamagnetic behaviour?

1. 
2. 
3. 
4. NO

Sol: , and NO are paramagnetic due to the presence of 2, 1 and 1 unpaired electrons respectively. will have no unpaired electron and is diamagnetic in nature. Correct choice: (1)

Q. 34. The stability of dihalides of Si, Ge, Sn and Pb increases steadily in the sequence

1. GeX₂ << SiX₂ << SnX₂ << PbX₂
2. SiX₂ << GeX₂ << PbX₂ << SnX₂
3. SiX₂ << GeX₂ << SnX₂ << PbX2
4. PbX₂ << SnX₂ << GeX₂ << SiX₂

Sol: The stability of the lower oxidation state increases down the group in group 14. SiX₂ << GeX₂ << SnX₂ << PbX₂ Correct choice: (3)

Q. 35. Identify the incorrect statement among the following:

1. Ozone reacts with SO₂ to give SO₃.
2. Silicon reacts with NaOH(aq) in the presence of air to give Na2SiO₃ and H₂O.
3. Cl₂ reacts with excess of NH₃ to give N₂ and HCl.
4. Br₂ reacts with hot and strong NaOH solution to give NaBr, NaBrO₄ and H₂O.

Sol: O₃ + SO₂ SO₃ + O₂
Si + 2NaOH + O₂ Na₂SiO₃ + H₂O
3Cl₂ + 2NH₃ N₂ + 6HCl
3Br₂ + 6NaOH  5NaBr + NaBrO₃ + 3H₂O Correct choice: (4)

Q. 36. The charge/size ratio of a cation determines its polarizing power. Which one of the following sequences represents the increasing order of the polarizing power of the cationic species, K⁺, Ca²⁺, Mg²⁺, Be²⁺?

Sol: Greater the charge/size ratio of a cation, size but charge of all those ions is same. Thus, polarising power of these ions is in the order: K⁺ has a 1 unit charge less than that of Ca²⁺ and its size is larger than that of Ca²⁺, thus polarising power of K⁺ is less than that of Ca²⁺. So, the correct order is
Correct choice: (3)