Which of the following has been arranged correctly in increasing order of acidic strength?

Options

A. `HF lt HCI lt HBr lt H I`
B. `H_(3) PO_(2) lt H_(3) PO_(3) lt H_(3) PO_(4)`
C. `H_(3)PO_(4) lt H_(2)SO_(4) lt HCIO_(4)`
D. `NH_(3) lt PH_(3) lt AsH_(3) lt BiH_(3)`

Answer

To determine the correct increasing order of acidic strength among the given compounds, we can analyze the acidic strength based on the properties of the compounds involved. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Compounds
The question presents several compounds, and we need to analyze their acidic strengths. Let's consider the compounds mentioned in the transcript: HF, HCl, HBr, HI, H3PO2, H3PO3, H3PO4, H2SO4, HClO4, and hydrides of nitrogen family (NH3, PH3, AsH3, SbH3).

### Step 2: Analyze Halogen Acids (HF, HCl, HBr, HI)
- **HF (Hydrofluoric acid)**: Weak acid due to strong H-F bond.
- **HCl (Hydrochloric acid)**: Strong acid, dissociates completely in water.
- **HBr (Hydrobromic acid)**: Strong acid, stronger than HCl.
- **HI (Hydroiodic acid)**: Strongest among these due to weaker H-I bond.

**Increasing order of acidic strength**: HF < HCl < HBr < HI

### Step 3: Analyze Phosphoric Acids (H3PO2, H3PO3, H3PO4)
- **H3PO2 (Phosphorous acid)**: Has one acidic hydrogen.
- **H3PO3 (Phosphoric acid)**: Has two acidic hydrogens.
- **H3PO4 (Phosphoric acid)**: Has three acidic hydrogens.

The more hydroxyl (OH) groups present, the stronger the acid because more protons can be released.

**Increasing order of acidic strength**: H3PO2 < H3PO3 < H3PO4

### Step 4: Analyze Sulfuric and Chloric Acids (H2SO4, HClO4)
- **H2SO4 (Sulfuric acid)**: Strong acid, can donate two protons.
- **HClO4 (Perchloric acid)**: One of the strongest acids, can donate one proton.

**Increasing order of acidic strength**: H2SO4 < HClO4

### Step 5: Analyze Nitrogen Family Hydrides (NH3, PH3, AsH3, SbH3)
- **NH3 (Ammonia)**: Weak base, very weak acid.
- **PH3 (Phosphine)**: Weaker base than NH3, slightly more acidic.
- **AsH3 (Arsine)**: Weaker base, slightly more acidic than PH3.
- **SbH3 (Stibine)**: Weakest base, strongest acid among these.

**Increasing order of acidic strength**: NH3 < PH3 < AsH3 < SbH3

### Final Conclusion
After analyzing the compounds, we can summarize the increasing order of acidic strength for the groups mentioned in the question:

1. For halogen acids: **HF < HCl < HBr < HI**
2. For phosphoric acids: **H3PO2 < H3PO3 < H3PO4**
3. For sulfuric and chloric acids: **H2SO4 < HClO4**
4. For nitrogen family hydrides: **NH3 < PH3 < AsH3 < SbH3**