The `K_(a)` of monobasic acid `P, Q` and R are `10^(-6),10^(-8)` and `10^(-10)` respectively.
The concentrations of P, Q and R are respectively
0.1M, 0.01 M and 0.001 M .
Q. Which of the following is true?

Options

A. P is weakest acid
B. Q is strongest acid
C. R is weakest acid
D. R is strongest acid

Answer

To solve the problem, we need to analyze the given information about the monobasic acids P, Q, and R based on their dissociation constants (Ka) and concentrations.

### Step-by-Step Solution:

1. **Identify the Ka Values**:
- For acid P: \( K_a = 10^{-6} \)
- For acid Q: \( K_a = 10^{-8} \)
- For acid R: \( K_a = 10^{-10} \)

2. **Understand the Relationship Between Ka and Acidity**:
- The strength of an acid is directly related to its \( K_a \) value. A higher \( K_a \) indicates a stronger acid because it means the acid dissociates more in solution, releasing more hydrogen ions (H⁺).

3. **Rank the Acids Based on Ka Values**:
- Comparing the \( K_a \) values:
- P has the highest \( K_a \) (10⁻⁶), making it the strongest acid.
- Q has a \( K_a \) of 10⁻⁸, making it weaker than P but stronger than R.
- R has the lowest \( K_a \) (10⁻¹⁰), making it the weakest acid.
- Therefore, the order of acidity is:
- Strongest: P > Q > R : Weakest

4. **Evaluate the Given Statements**:
- P is the weakest acid: **False** (P is the strongest acid)
- Q is the strongest acid: **False** (P is the strongest acid)
- R is the weakest acid: **True** (R is indeed the weakest acid)
- R is the strongest acid: **False** (R is the weakest acid)

5. **Conclusion**:
- The correct statement is: **R is the weakest acid**.

### Final Answer:
The true statement is: **R is the weakest acid**.

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