Assertion: `H_(3)PO_(4)` and `H_(3)PO_(3)` both are present in fertilizers.
Reason: `H_(3)PO_(3)` increases the solubility of fertilizers.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both asertion and reason are false.

Answer

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

### Step 1: Analyze the Assertion
The assertion states that \( H_3PO_4 \) (phosphoric acid) and \( H_3PO_3 \) (phosphorous acid) are both present in fertilizers.

- **Explanation**: Both \( H_3PO_4 \) and \( H_3PO_3 \) are indeed oxoacids of phosphorus and are commonly used in fertilizers. They provide essential phosphorus, which is a vital nutrient for plants.

### Step 2: Analyze the Reason
The reason states that \( H_3PO_3 \) increases the solubility of fertilizers.

- **Explanation**: While \( H_3PO_3 \) is used in fertilizers, it is not primarily because it increases solubility. Instead, it is known for its reducing properties, which can be beneficial in certain chemical reactions in fertilizers. The assertion that it increases solubility is incorrect.

### Step 3: Conclusion
Based on the analysis:
- The assertion is **true**: \( H_3PO_4 \) and \( H_3PO_3 \) are present in fertilizers.
- The reason is **false**: \( H_3PO_3 \) does not increase the solubility of fertilizers.

Thus, the correct answer is that the assertion is true, but the reason is false.

### Final Answer
Assertion is true, but reason is false.

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