# Nitormethane (incomplete) combustion

**URL:** <https://boards.straightdope.com/t/nitormethane-incomplete-combustion/558810>\
**Category:** Factual Questions\
**Created:** [October 29, 2010, 8:10pm UTC](https://boards.straightdope.com/t/nitormethane-incomplete-combustion/558810 "2010-10-29T20:10:00Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![nitromethane](https://avatars.discourse-cdn.com/v4/letter/n/ee59a6/32.png) [@nitromethane](https://boards.straightdope.com/u/nitromethane)\
**Post date:** [October 29, 2010, 8:10pm UTC](https://boards.straightdope.com/t/nitormethane-incomplete-combustion/558810/1 "2010-10-29T20:10:00Z")

</div>

Nitromethane is CH3NO2 (nitro for short). It is used a racing fuel, amongst other  
things. When used in racing, it is generally mixed with methanol in a 90%/10%  
ratio.

When that mixture is combusted (assume incomplete combustion here), one of the  
by-products is HNO3 (fun, fun stuff known as nitric acid).

Anyone with a chemistry back ground want to take this on and tell me what the  
reaction formula is? In the application I am speaking of, you may assume one part  
nitro/methanol mix to 1 part air (not O2). I don’t necessarily want the entire  
formula. Just tell me how nitric acid is produced and I would be happy.

---

<div class="post-metadata">

**Author:** ![matt](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@matt](https://boards.straightdope.com/u/matt)\
**Post date:** [October 29, 2010, 11:48pm UTC](https://boards.straightdope.com/t/nitormethane-incomplete-combustion/558810/2 "2010-10-29T23:48:32Z")

</div>

Just a standard gasoline IC engine will produce nitrogen oxides if it burns lean, because of the high temperatures and the presence of nitrogen and oxygen in the cylinder air. Incomplete combustion of nitromethane may leave NO and or NO[sub]2[/sub] as a byproduct.

Nitrogen oxides and oxygen dissolving into the H[sub]2[/sub]O also produced as a combustion product makes nitric acid. There’s a number of reactions that can happen:

4NO[sub]2[/sub] + 2H[sub]2[/sub]O + O[sub]2[/sub] --\> 4HNO[sub]3[/sub]

and 2NO[sub]2[/sub] + H[sub]2[/sub]O --\> HNO[sub]2[/sub] + HNO[sub]3[/sub]

then 3HNO[sub]2[/sub] --\> HNO[sub]3[/sub] + H[sub]2[/sub]O + 2NO

---

<div class="post-metadata">

**Author:** ![nitromethane](https://avatars.discourse-cdn.com/v4/letter/n/ee59a6/32.png) [@nitromethane](https://boards.straightdope.com/u/nitromethane)\
**Post date:** [October 31, 2010, 12:06am UTC](https://boards.straightdope.com/t/nitormethane-incomplete-combustion/558810/3 "2010-10-31T00:06:26Z")

</div>

Thanks!