For the following reaction `C_6H_(12)(aq)+H_2(g)hArrC_6H_(14)O_6(aq)`
Which one of the following is not affected by the addition of catalyst ?

Options

A. Rate of forward reaction
B. Rate of backward reaction
C. Time required to reach the equilibrium
D. Spontaneity

Answer

To solve the question regarding the effect of a catalyst on the given reaction \( C_6H_{12}(aq) + H_2(g) \rightleftharpoons C_6H_{14}O_6(aq) \), we need to analyze how a catalyst influences different aspects of a chemical reaction.

### Step-by-Step Solution:

1. **Understanding the Role of a Catalyst**:
- A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. It achieves this by providing an alternative reaction pathway with a lower activation energy.

2. **Effect on Forward and Backward Reaction Rates**:
- A catalyst increases the rate of both the forward and backward reactions equally. This means that the addition of a catalyst will speed up the formation of products from reactants and also the conversion of products back to reactants.

3. **Effect on Time Required to Reach Equilibrium**:
- Since a catalyst accelerates both the forward and backward reactions, it helps the system reach equilibrium faster. However, it does not change the position of the equilibrium or the equilibrium constant.

4. **Effect on Spontaneity of the Reaction**:
- Spontaneity refers to whether a reaction can occur without external intervention, which is determined by the Gibbs free energy change (\( \Delta G \)) of the reaction. A catalyst does not alter the Gibbs free energy of the reactants or products, and thus it does not affect the spontaneity of the reaction.

5. **Conclusion**:
- Among the options given:
- Rate of forward reaction: Affected by catalyst (increases).
- Rate of backward reaction: Affected by catalyst (increases).
- Time required to reach equilibrium: Affected by catalyst (decreases).
- Spontaneity: Not affected by catalyst.
- Therefore, the correct answer to the question is that the spontaneity of the reaction is not affected by the addition of a catalyst.

### Final Answer:
The option that is not affected by the addition of a catalyst is **spontaneity**.