Cyclohexanol is dehydrated to cyclohexene on heating with conc. `H_(2)SO_(4)`. If the yeild of this reaction is 75% ,how much cyclohexene will be obtained from 100 g of cyclohexanol ?
`C_(6)H_(12)O overset("conc." H_(2)SO_(4))to C_(6)H_(10)`

Answer

To solve the problem of how much cyclohexene will be obtained from 100 g of cyclohexanol with a yield of 75%, we can follow these steps:

### Step 1: Write the balanced chemical equation
The dehydration of cyclohexanol (C6H11OH) to cyclohexene (C6H10) can be represented as:
\[ \text{C}_6\text{H}_{11}\text{OH} \xrightarrow{\text{conc. } H_2SO_4} \text{C}_6\text{H}_{10} + \text{H}_2\text{O} \]

### Step 2: Calculate the molar mass of cyclohexanol
The molar mass of cyclohexanol (C6H11OH) can be calculated as follows:
- Carbon (C): 12 g/mol × 6 = 72 g/mol
- Hydrogen (H): 1 g/mol × 12 = 12 g/mol
- Oxygen (O): 16 g/mol × 1 = 16 g/mol

Adding these together:
\[ 72 + 12 + 16 = 100 \text{ g/mol} \]

### Step 3: Calculate the number of moles of cyclohexanol
Given that we have 100 g of cyclohexanol, we can calculate the number of moles:
\[ \text{Number of moles} = \frac{\text{mass}}{\text{molar mass}} = \frac{100 \text{ g}}{100 \text{ g/mol}} = 1 \text{ mole} \]

### Step 4: Determine the theoretical yield of cyclohexene
From the balanced equation, we see that 1 mole of cyclohexanol produces 1 mole of cyclohexene. Therefore, the theoretical yield of cyclohexene in grams can be calculated by finding its molar mass:
- Molar mass of cyclohexene (C6H10):
- Carbon (C): 12 g/mol × 6 = 72 g/mol
- Hydrogen (H): 1 g/mol × 10 = 10 g/mol

Adding these together:
\[ 72 + 10 = 82 \text{ g/mol} \]

Since we have 1 mole of cyclohexanol, the theoretical yield of cyclohexene is:
\[ 1 \text{ mole} \times 82 \text{ g/mol} = 82 \text{ g} \]

### Step 5: Calculate the experimental yield using the percentage yield
The experimental yield can be calculated using the percentage yield formula:
\[ \text{Experimental yield} = \left( \frac{\text{Percentage yield}}{100} \right) \times \text{Theoretical yield} \]

Substituting the values:
\[ \text{Experimental yield} = \left( \frac{75}{100} \right) \times 82 \text{ g} = 0.75 \times 82 = 61.5 \text{ g} \]

### Conclusion
The amount of cyclohexene that will be obtained from 100 g of cyclohexanol is **61.5 grams**.

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