(A): Orthophosphoric acid can form two acidic salts and one normal salt
(R): Orthophosphoric acid is a tribasic acid

Options

A. Both A & R are true, R is the correct explanation of A
B. Both A & R are true, R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true

Answer

To solve the question, we need to analyze both the assertion and the reason provided.

### Step 1: Understanding Orthophosphoric Acid
- **Assertion (A)**: Orthophosphoric acid can form two acidic salts and one normal salt.
- **Reason (R)**: Orthophosphoric acid is a tribasic acid.

### Step 2: Identify the Structure and Basicity of Orthophosphoric Acid
- The formula of orthophosphoric acid is H₃PO₄.
- It contains three replaceable hydrogen ions, which indicates that it is a tribasic acid. This means it can donate three protons (H⁺ ions).

### Step 3: Formation of Salts
- When orthophosphoric acid reacts with a base (like sodium hydroxide), it can form different types of salts:
1. **Normal Salt**: When all three hydrogen ions are replaced, we get sodium phosphate (Na₃PO₄).
2. **Acidic Salts**: When one or two hydrogen ions are replaced, we get:
- Sodium dihydrogen phosphate (NaH₂PO₄) - one acidic salt.
- Disodium hydrogen phosphate (Na₂HPO₄) - another acidic salt.

### Step 4: Conclusion on Assertion and Reason
- The assertion is correct because orthophosphoric acid can indeed form two acidic salts (NaH₂PO₄ and Na₂HPO₄) and one normal salt (Na₃PO₄).
- The reason is also correct because orthophosphoric acid is a tribasic acid.
- However, the reason does not directly explain the assertion. The assertion is about the types of salts formed, while the reason discusses the basicity of the acid.

### Final Answer
Both the assertion and the reason are true, but the reason is not the correct explanation for the assertion.

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