What is the maximum percentage of available chlorine in a sample of bleaching powder ?

Answer

To find the maximum percentage of available chlorine in a sample of bleaching powder (Ca(OCl)2), we will follow these steps:

### Step 1: Determine the Chemical Formula of Bleaching Powder
Bleaching powder is chemically represented as Ca(OCl)2, which consists of calcium (Ca), oxygen (O), and chlorine (Cl).

### Step 2: Calculate the Molar Mass of Bleaching Powder (Ca(OCl)2)
To calculate the molar mass, we need to sum the atomic masses of all the atoms in the formula:
- Atomic mass of Calcium (Ca) = 40 g/mol
- Atomic mass of Oxygen (O) = 16 g/mol
- Atomic mass of Chlorine (Cl) = 35.5 g/mol

The formula Ca(OCl)2 contains:
- 1 Calcium atom
- 2 Oxygen atoms
- 2 Chlorine atoms

Calculating the molar mass:
- Molar mass of Ca = 40 g/mol
- Molar mass of O = 2 × 16 g/mol = 32 g/mol
- Molar mass of Cl = 2 × 35.5 g/mol = 71 g/mol

Now, adding them together:
\[ \text{Molar mass of Ca(OCl)2} = 40 + 32 + 71 = 143 \, \text{g/mol} \]

### Step 3: Calculate the Mass of Available Chlorine
The mass of chlorine in one mole of bleaching powder is 71 g (from the calculation of 2 × 35.5 g/mol).

### Step 4: Calculate the Percentage of Available Chlorine
To find the percentage of available chlorine in bleaching powder, we use the formula:
\[ \text{Percentage of available chlorine} = \left( \frac{\text{Mass of chlorine}}{\text{Molar mass of bleaching powder}} \right) \times 100 \]
Substituting the values we calculated:
\[ \text{Percentage of available chlorine} = \left( \frac{71}{143} \right) \times 100 \]

Calculating this gives:
\[ \text{Percentage of available chlorine} = 49.65\% \]

### Final Answer
The maximum percentage of available chlorine in a sample of bleaching powder is approximately **49.65%**.

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