Oxidation Number And Oxidation States

Oleum is also known as fuming sulfuric acid.
Its chemical formula is or can be represented as .
This indicates that oleum is formed by the reaction of sulfuric acid ( ) with sulfur trioxide ( ).
Therefore, X and Y are and (or vice versa).
The central atom in both compounds is sulfur (S).
Let's determine the oxidation state of sulfur in each compound: **In :** The oxidation state of hydrogen (H) is +1.
The oxidation state of oxygen (O) is -2.
Let the oxidation state of sulfur (S) be .
The sum of the oxidation states in a neutral molecule is zero: $ is +6.
**In :** The oxidation state of oxygen (O) is -2.
Let the oxidation state of sulfur (S) be .
The sum of the oxidation states in a neutral molecule is zero: \) is +6.
The sum of the oxidation states of the central atom (sulfur) in X and Y is: \) $ Therefore, the sum of the oxidation states of the central atom in X and Y is 12.

Step 1: Identify Gas X from Deacon's process
In Deacon's process, chlorine gas (Cl ) is produced by catalytic oxidation of hydrogen chloride: Thus, X = Cl Step 2: Reaction with iodine and water
Chlorine reacts with iodine and water to form iodic acid:

The reaction of white phosphorus (P ) with concentrated NaOH solution is a disproportionation reaction.
The balanced chemical equation is: - Salt 'X' is sodium hypophosphite, NaH PO .
- Gas 'Y' is phosphine, PH .
The inert atmosphere of CO is used to prevent the highly flammable PH from catching fire (as O would cause combustion).
Oxidation state of phosphorus in reactants: In P , phosphorus is in its elemental state, so its oxidation state is 0.
Oxidation state of phosphorus in salt 'X' (NaH PO ): Na is +1.
H is +1 (when bonded to non-metal like P or O).
O is -2.
Let the oxidation state of P be .
In H PO ion (hypophosphite ion): (charge of the ion) .
So, the oxidation state of P in NaH PO is +1.
Oxidation state of phosphorus in gas 'Y' (PH ): H is generally +1 when bonded to a more electronegative non-metal.
Phosphorus is more electronegative than hydrogen (P: 2.
19, H: 2.
20 - very close, but convention often treats H as +1 with p-block elements unless they are very electropositive like metals for hydrides).
However, in phosphine, phosphorus is considered to be more electronegative than hydrogen for assigning oxidation states in this context (or use formal charge arguments).
Let oxidation state of P be .
(overall charge of molecule) .
So, the oxidation state of P in PH is -3.
The oxidation states of the central atom (P) in X and Y are +1 and -3, respectively.
This matches option (2).

The reaction of white phosphorus (P ) with concentrated NaOH solution is a disproportionation reaction.
The balanced chemical equation is: - Salt 'X' is sodium hypophosphite, NaH PO .
- Gas 'Y' is phosphine, PH .
The inert atmosphere of CO is used to prevent the highly flammable PH from catching fire (as O would cause combustion).
Oxidation state of phosphorus in reactants: In P , phosphorus is in its elemental state, so its oxidation state is 0.
Oxidation state of phosphorus in salt 'X' (NaH PO ): Na is +1.
H is +1 (when bonded to non-metal like P or O).
O is -2.
Let the oxidation state of P be .
In H PO ion (hypophosphite ion): (charge of the ion) .
So, the oxidation state of P in NaH PO is +1.
Oxidation state of phosphorus in gas 'Y' (PH ): H is generally +1 when bonded to a more electronegative non-metal.
Phosphorus is more electronegative than hydrogen (P: 2.
19, H: 2.
20 - very close, but convention often treats H as +1 with p-block elements unless they are very electropositive like metals for hydrides).
However, in phosphine, phosphorus is considered to be more electronegative than hydrogen for assigning oxidation states in this context (or use formal charge arguments).
Let oxidation state of P be .
(overall charge of molecule) .
So, the oxidation state of P in PH is -3.
The oxidation states of the central atom (P) in X and Y are +1 and -3, respectively.
This matches option (2).

Step 1: Understanding Boiling Point Trends For group 16 hydrides, boiling points increase down the group due to increasing molecular mass, except for water ( ), which exhibits strong hydrogen bonding. Step 2: Expected Boiling Point Order - Water has an exceptionally high boiling point due to hydrogen bonding. - The correct trend is: Since option (C) incorrectly places last, it is incorrect. Conclusion Thus, the correct answer is:

Step 1: Understanding Boiling Point Trends For group 16 hydrides, boiling points increase down the group due to increasing molecular mass, except for water ( ), which exhibits strong hydrogen bonding. Step 2: Expected Boiling Point Order - Water has an exceptionally high boiling point due to hydrogen bonding. - The correct trend is: Since option (C) incorrectly places last, it is incorrect. Conclusion Thus, the correct answer is:

P O is a strong dehydrating agent. It reacts with nitric acid to form dinitrogen pentoxide (N O ).
Elemental phosphorus (P ) reacts with nitric acid to produce nitrogen dioxide (NO ) and phosphoric acid.