Sure, let's solve each part of the question step-by-step:
### ii. Oxidation number of nitrogen in [tex]\(HNO_3\)[/tex]:
1. The oxidation number of hydrogen ([tex]\(H\)[/tex]) is usually +1.
2. The oxidation number of oxygen ([tex]\(O\)[/tex]) is usually -2.
3. Let the oxidation number of nitrogen ([tex]\(N\)[/tex]) be [tex]\(x\)[/tex].
The compound is neutral, so the sum of oxidation numbers must equal 0.
[tex]\[ 1 \cdot (+1) + 1 \cdot x + 3 \cdot (-2) = 0 \][/tex]
[tex]\[ +1 + x - 6 = 0 \][/tex]
[tex]\[ x - 5 = 0 \][/tex]
[tex]\[ x = +5 \][/tex]
So, the oxidation number of nitrogen in [tex]\(HNO_3\)[/tex] is [tex]\(\boxed{+5}\)[/tex].
### iii. Oxidation number of oxygen in [tex]\(OF_2\)[/tex]:
1. The oxidation number of fluorine ([tex]\(F\)[/tex]) is always -1 (the most electronegative element).
2. Let the oxidation number of oxygen ([tex]\(O\)[/tex]) be [tex]\(y\)[/tex].
The compound [tex]\(OF_2\)[/tex] is neutral, so the sum of oxidation numbers must equal 0.
[tex]\[ y + 2 \cdot (-1) = 0 \][/tex]
[tex]\[ y - 2 = 0 \][/tex]
[tex]\[ y = +2 \][/tex]
So, the oxidation number of oxygen in [tex]\(OF_2\)[/tex] is [tex]\(\boxed{+2}\)[/tex].
### iv. Reducing agent is a substance that itself:
A reducing agent donates electrons in a chemical reaction and is itself oxidized.
So, the reducing agent is a substance that itself [tex]\(\boxed{\text{oxidize}}\)[/tex].
### v. In the redox reaction between Zn and HCl, the oxidizing agent is:
The redox reaction between zinc (Zn) and hydrochloric acid (HCl) can be represented as:
[tex]\[ \text{Zn}_{(s)} + 2 \text{HCl}_{(aq)} \rightarrow \text{ZnCl}_{2(aq)} + \text{H}_2{(g)} \][/tex]
- Zinc (Zn) is oxidized to Zn[tex]\(^{2+}\)[/tex], losing electrons:
[tex]\[ \text{Zn} \rightarrow \text{Zn}^{2+} + 2e^- \][/tex]
- Hydrogen ions (H[tex]\(^+\)[/tex]) gain the electrons and form hydrogen gas (H[tex]\(_2\)[/tex]):
[tex]\[ 2 \text{H}^+ + 2e^- \rightarrow \text{H}_2 \][/tex]
The species that gains electrons (is reduced) is the oxidizing agent. Here, [tex]\(H^+\)[/tex] is reduced to [tex]\(H_2\)[/tex].
So, the oxidizing agent is [tex]\(\boxed{\text{H}^+}\)[/tex].
### Summary:
- ii: The oxidation number of nitrogen in [tex]\(HNO_3\)[/tex] is [tex]\(\boxed{+5}\)[/tex].
- iii: The oxidation number of oxygen in [tex]\(OF_2\)[/tex] is [tex]\(\boxed{+2}\)[/tex].
- iv: A reducing agent is a substance that itself [tex]\(\boxed{\text{oxidize}}\)[/tex].
- v: The oxidizing agent in the reaction between Zn and HCl is [tex]\(\boxed{\text{H}^+}\)[/tex].
