Which of the following carbohydrates does not have the formula `C_12H_22O_11` ?

Options

A. Galactose
B. Sucrose
C. Allolactose
D. Maltose

Answer

To determine which carbohydrate does not have the formula \( C_{12}H_{22}O_{11} \), we need to analyze the carbohydrates provided in the options. The formula \( C_{12}H_{22}O_{11} \) corresponds to disaccharides, which are formed by the combination of two monosaccharide units.

### Step-by-Step Solution:

1. **Understanding Carbohydrate Types**:
- Carbohydrates can be classified into monosaccharides, disaccharides, and polysaccharides.
- Monosaccharides have the general formula \( C_nH_{2n}O_n \) (e.g., glucose, fructose, galactose).
- Disaccharides are formed by the condensation of two monosaccharides and typically have the formula \( C_{n}H_{2n-2}O_{n-1} \) (e.g., sucrose, maltose, lactose).

2. **Identifying the Formula**:
- The formula \( C_{12}H_{22}O_{11} \) indicates a disaccharide, as it consists of two monosaccharide units.
- Examples of disaccharides with this formula include sucrose (glucose + fructose), maltose (glucose + glucose), and lactose (glucose + galactose).

3. **Analyzing Galactose**:
- Galactose is a monosaccharide with the formula \( C_6H_{12}O_6 \).
- Since it is not a disaccharide, it cannot have the formula \( C_{12}H_{22}O_{11} \).

4. **Conclusion**:
- From the analysis, we can conclude that galactose does not have the formula \( C_{12}H_{22}O_{11} \). Therefore, it is the carbohydrate that does not fit the given formula.

### Final Answer:
Galactose does not have the formula \( C_{12}H_{22}O_{11} \).