A) Account for the following:

1) Bi is a strong oxidising agent in the +5 state.

2) is known but is not known.

3) dissolves in HCl to form and not

B) Draw the structures of the following:

1)

2)

OR

A) Draw the structures of the following:

i)

ii) Red

B) Account for the following:

i) Sulphur is vapour state exhibits paramagnetism

ii) Unlike, Xenon, no distinct chemical compound of Helium is known.

iii) is a stronger reducing agent than .

A) 1) The lower oxidation state becomes more stable due to inert pair effect. Thus, for Bismuth, the +3oxidation state would be more stable than the +5 oxidation state. As a result, Bi will show a strong tendency to change into the +3 state from the +5 state. So, as the stability of +5 oxidation state is less than that of +3, therefore, Bi+5 is a strong oxidising agent.

2) In the case of P, Phosphorous has available d-orbitals and therefore it can accommodate electrons from Chlorine into vacant orbitals.But in case of N the d-orbitals are absent and electrons can be accommodated only in p- orbitals. Hence exists but does not exists.

3) The Hydrogen atoms bond together to create Hydrogen gas, and the two Chloride will bond with the Iron. Since, each Chloride has -1 charge, and the Fe has +2 charge in its valence shell. The 2 electrons will each form bond with one Chloride ion. Thus, Iron forms two bonds,in which one single bond to each chloride. Since its valance shell has been exhausted and there are no other unbonded elements in the equation, as Iron cannot extend its orbit to obtain another electron,thus, it cannot form Fe+3 ion (which would make iron (III) chloride).

3) B) i)

ii)

OR

A) i)

B) i) The paramagnetism in Sulphur in vapour phase can be explained from the fact that in vapour phase, is the dominant species and is therefore paramagnetic like , which has two unpaired electrons. So like molecule, also has two unpaired electrons in the π*px and π*py orbital.

Further,

The EC of Sulphur atom is . Each Sulphur atom has 16 electrons, hence, in molecule there are 32 electrons. The EC of the molecule is

ii) As the size of the Helium atom is extremely small as compared to Xenon and also due to unavailability of empty outer shell or completely filled outer orbits. Helium is not reactive in nature, whereas Xenon has a comparatively bigger size and also it can accommodate or extend its outer most shell to form compounds with other elements.

Therefore, Xenon difluoride, Xenon trifluoride are known but Helium compounds.

iii)

The hydrogen atoms in OH bond is ionizable and are acidic whereas the P-H bonds have reducing property. The number of P-H bonds is maximum in . So, it is the strongest reducing agent followed by . is not a reducing agent as it has completely oxidized and cannot accept more oxygen atoms, hence, it not an oxidising agent.