Answer the following:
a. Which of the following has the greatest affinity for water: `P_(4)O_(10). Cl_(2)O,I_(2)O_(5)`.
b. Which of the following is the most basic: `Al_(2)O_(3), TI_(2)O_(3),TI_(2)O`.
c. Which of the following has the lowest melting point: `LiBr,Be,BBr_(3)`.
d. Which of the following has higher `EN:Li, Be,Mg`.
e. Which of the following is most stable towards oxidation: `GeCl_(2),SnCl_(2),PbCl_(2)`.
f. Which of the following is the strongest oxidising agent:
`CrO_(4)^(2-),MoO_(4)^(2-),WO_(4)^(2-)`.

Explanation

`P_(4)O_(10)`. It is more powerful as a dehydrating agent than `Cl_(2)O_(7)` since the latters is the product of dehydration of `HClO_(4)` by `P_(4)O_(10)`. Reverse reaction does not proceed so well.
Since `I_(2)O_(5)` can be prepared by heating `HIO_(3)`, it cannot have too great an affininty of water. In fact ,`P_(4)O_(10)` is one of the most powerful dehydrating agents known.
b. Apply Fajan's rule, more ionic a compound more basic it is ( large cation and less charge.) So, `TI_(2)O` is more basic.
Therefore, basic or ionic order is
`overset(1+)(Tl_(2))O gt overset(3+)(Tl_(2)O_(3)) gt overset(3+)(Al_(2)O_(3)`
c. Apply Fajans' rule, more covalent a compound, lesser is the melting point ( small cation and high charge).
Covalent character order: `overset(3+)(B Br_(3)) gt overset(2+)(BeBr_(2))gt overset(o+)(LiBr)`
Melting point order: `BBr_(3) lt BeBr_(2) lt LiBr`
d. `EN` increase along the period, i.e., from `Li` to `Be` ( `2` nd period) but decreases down the group. So, `Be` is the most `EN` element. Order of `EN: Be ( 1.5 ) gt Mg (1.2) gt Li (1.0)`
(e) `PbCl_(2)`. The inert pair effect of the `6th` period element is more stable than those of the `5th` period elements and far more stable than the analogous pair in the `4 th` period.