Give the correct order of initials T of F for following statements. Use T if statements is true and F if it is false.
`I)` Sulphide reacts with `Na_(2)[Fe(CN)_(5)(NO)]` to form a purple coloured compound `Na_(4)[Fe(CN)_(5)(NOS)]` . In the reaction, the oxidation state of iron changes.
`II) Pt(IV)` compounds are relatively more stable than `Ni(IV)` compounds
`III)` The welding of magnesium can be done in the atmosphere of Helium.
`IV) LiAlH_(4)` on hydrolysis will give `H_(2)`

Options

A. FFTT
B. FTTT
C. TFTF
D. TFTT

Explanation

To solve the problem, we will evaluate each statement one by one and determine whether they are true (T) or false (F).

### Step-by-Step Solution:

**Statement I:**
"Sulfide reacts with `Na_(2)[Fe(CN)_(5)(NO)]` to form a purple colored compound `Na_(4)[Fe(CN)_(5)(NOS)]`. In the reaction, the oxidation state of iron changes."

1. **Identify the initial and final compounds:**
- Initial: `Na_(2)[Fe(CN)_(5)(NO)]`
- Final: `Na_(4)[Fe(CN)_(5)(NOS)]`

2. **Determine the oxidation state of iron in both compounds:**
- In `Na_(2)[Fe(CN)_(5)(NO)]`:
- Sodium (Na) = +1 (2 Na = +2)
- Cyanide (CN) = -1 (5 CN = -5)
- Nitric oxide (NO) = +1
- Let the oxidation state of iron be x.
- Therefore, +2 + x - 5 + 1 = 0 → x = +2.
- In `Na_(4)[Fe(CN)_(5)(NOS)]`:
- Sodium (Na) = +1 (4 Na = +4)
- Cyanide (CN) = -1 (5 CN = -5)
- Nitric oxide (NO) = +1
- Let the oxidation state of iron be y.
- Therefore, +4 + y - 5 + 1 = 0 → y = +2.

3. **Conclusion for Statement I:**
- The oxidation state of iron does not change in both compounds (remains +2).
- Therefore, Statement I is **False (F)**.

---

**Statement II:**
"Pt(IV) compounds are relatively more stable than Ni(IV) compounds."

1. **Consider the ionization energies:**
- Ionization energy for Pt(IV) is lower than that of Ni(IV).
- Lower ionization energy indicates greater stability of the compound.

2. **Conclusion for Statement II:**
- Since Pt(IV) compounds are indeed more stable than Ni(IV) compounds due to lower ionization energy, Statement II is **True (T)**.

---

**Statement III:**
"The welding of magnesium can be done in the atmosphere of Helium."

1. **Consider the reactivity of magnesium:**
- Magnesium reacts with oxygen and nitrogen in the air.
- Helium is a noble gas and does not react with magnesium.

2. **Conclusion for Statement III:**
- Therefore, welding of magnesium can be safely done in the atmosphere of Helium, making Statement III **True (T)**.

---

**Statement IV:**
"LiAlH_(4) on hydrolysis will give H_(2)."

1. **Consider the hydrolysis reaction:**
- The hydrolysis of LiAlH4 produces hydrogen gas (H2), aluminum hydroxide (Al(OH)3), and lithium hydroxide (LiOH).
- The reaction can be represented as:
\[ \text{LiAlH}_4 + 4 \text{H}_2\text{O} \rightarrow \text{Al(OH)}_3 + \text{LiOH} + 2 \text{H}_2 \]

2. **Conclusion for Statement IV:**
- Since hydrogen gas is indeed produced, Statement IV is **True (T)**.

---

### Final Order of Statements:
- I: F
- II: T
- III: T
- IV: T

Thus, the correct order of initials is **F T T T**.