Which soda is the most acidic? Coke? Pepsi? 7-up? Other?

1) Total acid level (pH):
This study gives the following two values:
"pH (acid) Level* Low number = bad for teeth
Sugar Amount** Per 12-ounce serving"

"Pure Water 7.00 (Neutral) 0.0
Coffee (Average, Black) 5.00 0.0
Barq’s Root Beer 4.61 10.71 tsp.
Diet Dr. Pepper 3.41 0.0
Juicy-Juice (Berry) 3.40 9.75 tsp.
Fresca 3.20 0.0
Diet Sprite 3.17 0.0
Red Bull Energy Drink 3.10 9.29 tsp.
Nestea 3.04 6.07 tsp.
Propel (Berry) 3.02 0.71 tsp.
Diet Mountain Dew 2.95 0.0
Dr. Pepper 2.92 9.64 tsp.
Sprite 2.90 9.29 tsp.
Gatorade (Lemon-Lime) 2.83 5 tsp.
Mountain Dew 2.80 11.07 tsp.
Minute Maid Orange Soda 2.80 11.2 tsp.
Diet Pepsi 2.77 0.0
Diet Coke 2.70 0.0
Powerade 2.63 5.36 tsp.
Pepsi 2.43 9.64 tsp.
Coca-Cola 2.30 9.64 tsp.
Battery Acid (Yikes!) 1.00 (Acidic) 0.0"

"*Acid amounts from the study “Enamel and root surface erosion due to popular U.S. beverages,” 2006. Authors: L. Ehlen, T.A. Marshall, F. Qian, J.J. Warren, J. Wefel, M.M. Hogan, and J.D. Harless. College of Dentistry, University of Iowa, Iowa City and from University of Minnesota School of Dentistry, 2000, Northwest Dentistry Vol 80, No. 2. **4.2 grams = 1 teaspoon."
Source and further information:
http://www.modental.org/docs/consumers/stp/stpbrochure.pdf


2) Kind of acid:
- ascorbic acid/vitamin C or erythorbic acid/d-ascorbic acid:
"Currently, the “big three” soda companies, PepsiCo, Coca-Cola, and Cadbury-Schweppes, are facing class action lawsuits over benzene-forming ingredients in their beverages-specifically PepsiCo’s Pepsi Twist, Vault Zero and Fanta Orange-Pineapple drinks from Coke, and Crush Pineapple from Cadbury. Keep in mind that though the lawsuits mention one or two specific drinks, other drinks from these companies may contain benzene-forming ingredients. (None of their flagship products, Coke, Diet Coke, Pepsi, Diet Pepsi, and Schweppes Ginger Ale, contained the ingredient combinations.) Other lawsuits against companies like Publix, Kraft Foods, Ocean Spray Cranberries, and Polar Beverages are also pending. Meridian, InZone Brands, and Talking Rain have settled similar lawsuits, agreeing to reformulate their drinks.

To protect your family’s health, look at ingredient labels, and steer clear of sodas, sports drinks, and juices containing ascorbic acid/vitamin C or erythorbic acid/d-ascorbic acid in combination with either sodium benzoate or potassium benzoate."

- phosphoric acid:
"CSPI’s report on soda consumption and health, Liquid Candy: How Soft Drinks are Harming Americans’ Health, states that drinking too much soda may also increase the risk of osteoporosis (because soda drinkers tend to drink less milk) and kidney stones (linked to the phosphoric acid in most sodas), according to some studies."
Source and further information:
http://www.killercoke.org/realmoneyfeb.htm

Here were the girl's results from the science project....it was to determine the Ph of different soft drinks:

The original purpose of this experiment was to determined the acidity of various sodas.

Here is the girl's full science project
http://www.selah.k12.wa.us/SOAR/SciProj2002/SaraW.html
The results of the experiment were Coke pH was 2.44, Pepsi pH was 2.46, Dr. Pepper pH was 2.93, Sprite pH was 2.88, Moutain Dew pH was 3.23, and Mug root beer pH was 4.06.

So coke had the lowest Ph, therefore being the most acidic=)

I am not sure what brands have more but I do know the dark sodas all have phosphoric acid, which removes calcium carbonate from teeth. not the answer I think you where looking for but it was the best I could come up with, (O: