Select the correct statement(s):

Options

A. When Al is added to potassium hydroxide solution, hyddrogenn gas is evolved
B. `H_(2)SiF_(6)` is formed when silica reaccts with hydrogen fluoride followed by hydrolysis
C. Phosphine gas is formed when red phosphorus is heated with NaOH
D. `(NH_(4))_(2)SO_(4)*FeSO_(4)*6H_(2)O` is called alums

Answer

To solve the question of selecting the correct statements from the given options, we will analyze each statement one by one.

### Step-by-Step Solution:

1. **Statement 1: When aluminum is added to potassium hydroxide solution, hydrogen gas is evolved.**
- When aluminum (Al) reacts with potassium hydroxide (KOH), it forms potassium aluminate (KAlO2) and hydrogen gas (H2). The reaction can be represented as:
\[ 2 \text{Al} + 2 \text{KOH} + 6 \text{H}_2\text{O} \rightarrow 2 \text{KAl(OH)}_4 + 3 \text{H}_2 \uparrow \]
- This statement is **correct**.

2. **Statement 2: H2SiF6 is formed when silica reacts with hydrogen fluoride followed by hydrolysis.**
- Silica (SiO2) reacts with hydrogen fluoride (HF) to form hexafluorosilicic acid (H2SiF6) upon hydrolysis. The reaction can be represented as:
\[ \text{SiO}_2 + 6 \text{HF} \rightarrow \text{H}_2\text{SiF}_6 + 2 \text{H}_2\text{O} \]
- This statement is also **correct**.

3. **Statement 3: Phosphine gas is formed when red phosphorus is heated with NaOH.**
- Phosphine (PH3) is actually produced when white phosphorus (P4) is treated with NaOH, not red phosphorus. The reaction involves heating white phosphorus with NaOH in the presence of water. Therefore, this statement is **incorrect**.

4. **Statement 4: NH4 whole twice SO4 into FeSO4 into 6 times H2O is called alum.**
- The compound \( \text{(NH}_4\text{)}_2\text{SO}_4 \cdot \text{FeSO}_4 \cdot 6 \text{H}_2\text{O} \) is known as Mohr's salt, not alum. Alum is a different type of compound, typically represented as \( \text{XAl}_2(\text{SO}_4)_3 \cdot 12 \text{H}_2\text{O} \), where X is a monovalent cation. Hence, this statement is also **incorrect**.

### Conclusion:
The correct statements are:
- Statement 1: Correct
- Statement 2: Correct
- Statement 3: Incorrect
- Statement 4: Incorrect

Thus, the correct answers are **Statement 1 and Statement 2**.