The standard reduction potential of `TiO^(2+)` and `Ti^(3+)` are given by
`TiO_(2+)+2H^(+)+e^(-)toTi^(3+)+H_(2)O" "E^(@)=0.10V`
`Ti^(3+)+3e^(-)toTi" "E^(@)=-1.21V`

Explanation

To find the standard reduction potential of the reaction \( \text{Ti}^{4+} + 4e^- \rightarrow \text{Ti} \), we can use the given standard reduction potentials for the reactions involving \( \text{Ti}^{2+} \) and \( \text{Ti}^{3+} \).

### Step-by-Step Solution:

1. **Identify the Given Reactions and Their Potentials:**
- The first reaction is:
\[ \text{Ti}^{2+} + 2\text{H}^+ + e^- \rightarrow \text{Ti}^{3+} + \text{H}_2\text{O} \quad E^\circ = 0.10 \, \text{V} \]
- The second reaction is:
\[ \text{Ti}^{3+} + 3e^- \rightarrow \text{Ti} \quad E^\circ = -1.21 \, \text{V} \]

2. **Write the Overall Reaction:**
- To find the potential for the reaction \( \text{Ti}^{4+} + 4e^- \rightarrow \text{Ti} \), we need to combine the two given reactions. We can express \( \text{Ti}^{4+} \) in terms of \( \text{Ti}^{3+} \):
\[ \text{Ti}^{4+} + 3e^- + 2\text{H}^+ \rightarrow \text{Ti}^{3+} + \text{H}_2\text{O} \]
- Then, we can combine it with the second reaction:
\[ \text{Ti}^{3+} + 3e^- \rightarrow \text{Ti} \]

3. **Calculate the Standard Reduction Potential:**
- The overall reaction combining both steps is:
\[ \text{Ti}^{4+} + 4e^- + 2\text{H}^+ \rightarrow \text{Ti} + \text{H}_2\text{O} \]
- The number of electrons transferred \( n \) in the first step is 1 and in the second step is 3, so the total \( n \) for the overall reaction is 4.
- We can use the formula for the overall standard potential:
\[ E^\circ_{\text{overall}} = E^\circ_1 + E^\circ_2 \]
- Here, \( E^\circ_1 = 0.10 \, \text{V} \) (for \( \text{Ti}^{2+} \) to \( \text{Ti}^{3+} \)) and \( E^\circ_2 = -1.21 \, \text{V} \) (for \( \text{Ti}^{3+} \) to \( \text{Ti} \)).
- Therefore:
\[ E^\circ_{\text{overall}} = 0.10 + (-1.21 \times 3) \]
- Calculating this gives:
\[ E^\circ_{\text{overall}} = 0.10 - 3.63 = -3.53 \, \text{V} \]

4. **Final Calculation:**
- The final standard reduction potential for the reaction \( \text{Ti}^{4+} + 4e^- \rightarrow \text{Ti} \) is:
\[ E^\circ = -0.8825 \, \text{V} \]

### Final Answer:
The standard reduction potential of \( \text{Ti}^{4+} + 4e^- \rightarrow \text{Ti} \) is \( -0.8825 \, \text{V} \).