## E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

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Dhamnekar Winod
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### E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

It is sometimes necessary to compute E° for a given half reaction from other half reaction of known E°.

For example, the standard electrode potential for the oxidation of Titanium metal to Ti³⁺ can be obtained from the following half reaction:
Ti²⁺ + 2 e⁻ ⇌ Ti⁰ E° = -1.63 Volts ①

Ti³⁺ + e⁻ ⇌ Ti²⁺ E° = -0.37 Volts ②

Calculate E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

My answer: ② is more spontaneous reaction than ①.

Reduction: Ti³⁺ + e⁻ ⇌ Ti²⁺ E° = -0.37 Volts ;

Oxidation: Ti²⁺ + 2 e⁻ ⇌ Ti⁰ E° = -1.63 Volts

Hence, $$E^\circ_{rx} = E^\circ_{red} - E^\circ_{ox} = -0.37 V - (-1.63 V) = + 1.26 V$$

But, Is my logic in answering this question correct?
Last edited by Dhamnekar Winod on Sat Aug 20, 2022 9:22 am, edited 1 time in total.
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

It can not match, because its negativ , its - 1,26 V

https://www.periodensystem-online.de/in ... 2&id=redox

You have to change both voltages.

E = -0,163 V -(-0,37V) = -1,26 V
Dhamnekar Winod
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Posts: 243
Joined: Sat Nov 21, 2020 10:14 am
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### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

Author has given the following answer:
E⁰ for Ti.png (7.9 KiB) Viewed 504 times
is there typographical error in the above answer?
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
Dhamnekar Winod
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Posts: 243
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay] and Mumbai Suburb,, Maharashtra State,India

### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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Location: Berlin, Germany

### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

Oxidation and Reduction is mixed up. Also for both voltages the same reaction is used. There is no reaction Ti 2+ to Ti 3 +.
Dhamnekar Winod
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Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay] and Mumbai Suburb,, Maharashtra State,India

### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

Why did you choose ① as reduction half reaction and ② as oxidation half reaction?

Would you explain that?
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
Dhamnekar Winod
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Posts: 243
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay] and Mumbai Suburb,, Maharashtra State,India

### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

Author's given answer is wrong.The correct answer is + 1.21 volts using the formula for ∆G°= -nFE°
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

No also in this case you lost one minus. In tables this gives - 1.21 V

https://www.periodensystem-online.de/in ... 2&id=redox
Dhamnekar Winod
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Posts: 243
Joined: Sat Nov 21, 2020 10:14 am
Location: Mumbai[Bombay] and Mumbai Suburb,, Maharashtra State,India

### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

The table in your link says Ti³⁺ + 3 e⁻ ⇌ Ti⁰ E° = -1.208 V

Reverse it for oxidation of Titanium metal Ti⁰ ⇌ Ti³⁺ + 3 e⁻ E° = +1.208 V
Any science consists of the following process. 1) See 2)Hear 3)Smell,if needed 4)Taste, if needed 5)Think 6)Understand 7)Inference 8)Take decision [Believe or disbelieve, useful or useless, true or false, cause or effect, any other criteria]
ChenBeier
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Joined: Wed Sep 27, 2017 7:25 am
Location: Berlin, Germany

### Re: E° for Ti⁰ ⇌ Ti³⁺ + 3 e⁻

The redox potential of a half reaction is measured to the hydrogen electrode.
So it doesn't matter if you look Ti 3+ + 3 e- => Ti or Ti => Ti 3+ + 3 e- . The voltage of 2 H+ +2 e- => H2 or H2 => 2 H+ +2 e- is 0 V
and the difference between both reaction is - 1,26 V.

Also in your postings it's given with the ⇌ sign. Also back and forward is the same regarding the potential.