What mass of barium chloride would be decomposed by `9.8 g` of sulphuric acid, if 12 g of barium sulphate and 2.75 g of hydrogen chloride were porduced in a reaction assuming that the law of conservation of mass is true?

Options

A. 5.6 g
B. 7.8 g
C. 3.1 g
D. 4.95 g

Answer

To solve the problem, we will apply the law of conservation of mass, which states that the total mass of the reactants must equal the total mass of the products in a chemical reaction.

### Step-by-Step Solution:

1. **Identify the Given Data:**
- Mass of sulfuric acid (H₂SO₄) = 9.8 g
- Mass of barium sulfate (BaSO₄) produced = 12 g
- Mass of hydrogen chloride (HCl) produced = 2.75 g

2. **Calculate the Total Mass of Products:**
\[ \text{Total mass of products} = \text{mass of BaSO₄} + \text{mass of HCl} \]
\[ \text{Total mass of products} = 12 \, \text{g} + 2.75 \, \text{g} = 14.75 \, \text{g} \]

3. **Apply the Law of Conservation of Mass:**
According to the law of conservation of mass:
\[ \text{Total mass of reactants} = \text{Total mass of products} \]
Let the mass of barium chloride (BaCl₂) be \( M \). Therefore:
\[ M + 9.8 \, \text{g} = 14.75 \, \text{g} \]

4. **Solve for the Mass of Barium Chloride (M):**
Rearranging the equation gives:
\[ M = 14.75 \, \text{g} - 9.8 \, \text{g} \]
\[ M = 4.95 \, \text{g} \]

5. **Conclusion:**
The mass of barium chloride that would be decomposed is **4.95 g**.