An element `A` (atomic weight = 12) and `B` (atomic weight = 35.5) combines ot form a compound `X`. If 5 mol of `B` comibnes with 1 mol of `A` to give 1 mol of `X`. The weight of 1 mol of `X` would be

Options

A. `47.5 g`
B. `74.0 g`
C. `154.0 g`
D. `148.0 g`

Explanation

To find the weight of 1 mole of the compound \( X \) formed by elements \( A \) and \( B \), we can follow these steps:

### Step 1: Identify the atomic weights
- The atomic weight of element \( A \) is given as 12.
- The atomic weight of element \( B \) is given as 35.5.

### Step 2: Determine the moles of elements combining to form \( X \)
- According to the problem, 1 mole of \( A \) combines with 5 moles of \( B \) to form 1 mole of \( X \).

### Step 3: Calculate the weight of element \( A \)
- The weight of 1 mole of \( A \) is simply its atomic weight:
\[ \text{Weight of } A = 1 \text{ mole} \times 12 \text{ g/mol} = 12 \text{ g} \]

### Step 4: Calculate the weight of element \( B \)
- The weight of 5 moles of \( B \) can be calculated as:
\[ \text{Weight of } B = 5 \text{ moles} \times 35.5 \text{ g/mol} = 5 \times 35.5 = 177.5 \text{ g} \]

### Step 5: Calculate the total weight of the compound \( X \)
- The total weight of the compound \( X \) is the sum of the weights of \( A \) and \( B \):
\[ \text{Weight of } X = \text{Weight of } A + \text{Weight of } B = 12 \text{ g} + 177.5 \text{ g} = 189.5 \text{ g} \]

### Conclusion
- Therefore, the weight of 1 mole of compound \( X \) is \( 189.5 \) grams.

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