Read the given statements and mark the correct option.
Statement 1 : `Mg, Ca` and `Sr` constitute a Dobereiner’s triad.
Statement 2: Atomic mass of `Ca` is an average of the atomic masses of `Mg` and `Sr`.

Options

A. Both statements 1 and 2 are true and statement 2 is the correct explanation of statement 1.
B. Both statements 1 and 2 are true but statement 2 is not the correct explanation of statement 1.
C. Statement 1 is true but statement 2 is false.
D. Both statements 1 and 2 are false.

Explanation

To determine the correctness of the given statements regarding Dobereiner’s triads, we will analyze each statement step by step.

### Step 1: Analyze Statement 1
**Statement 1:** `Mg, Ca` and `Sr` constitute a Dobereiner’s triad.

- **Definition of Dobereiner's Triad:** Dobereiner's triads consist of three elements where the atomic mass of the middle element is approximately the average of the atomic masses of the other two elements.

- **Atomic Masses:**
- Magnesium (Mg) = 24
- Calcium (Ca) = 40
- Strontium (Sr) = 88

- **Calculating the Average:**
- According to Dobereiner's triad, the average atomic mass of Mg and Sr should equal the atomic mass of Ca.
- Average = (Atomic mass of Mg + Atomic mass of Sr) / 2
- Average = (24 + 88) / 2 = 112 / 2 = 56

Since the average atomic mass (56) does not equal the atomic mass of Calcium (40), **Statement 1 is incorrect.**

### Step 2: Analyze Statement 2
**Statement 2:** The atomic mass of `Ca` is an average of the atomic masses of `Mg` and `Sr`.

- From our previous calculation, we found that the average atomic mass of Mg and Sr is 56, not 40.
- Therefore, the atomic mass of Calcium (Ca) is not the average of the atomic masses of Magnesium (Mg) and Strontium (Sr).

Thus, **Statement 2 is also incorrect.**

### Conclusion
Both statements are incorrect.

### Final Answer
Both Statement 1 and Statement 2 are incorrect.

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