the substitute is called cornflour. cornstach is just a diffrent name for cornflower
Cornstarch is a thickening agent. You can use flour, but will need a little more.
In food eggs
No; they are very different. Baking Soda is a leavening agent, salt is a mineral that enhances flavor, the two are definitely NOT interchangeable.
No, you shouldn't really substitute for eggs, but usually water and oil are used to substitue. (Not one or the other, a little of both)
Probably not. Baking mix has other ingredients such as baking soda/powder and dried milk or eggs. What type of baking mix is it and what are you making? If you're just battering something it will be fine, but if you're baking something, not so much.
I'm not positive. The reverse substitution is for 1 tsp. of baking powder, you use 1/4-1/2 tsp. of baking soda and 1/2 tsp. cream of tartar. So you could try using baking powder instead of cream of tartar, but it's not guaranteed. If there is supposed to be baking soda and cream of tartar in the recipe and you substituted baking powder, that would be more likely to succeed.
no
NO
Nothing..
I suppose that is possible.
Baking powder is a good alternative to baking soda. Yeast isn't recommended. You really can't subsitute it. After researching on the internet I have found that this is true, baking powder would be the only substitue.
Transformation of coal in a substitue of oil.
Yes, you can. Substitue 1/2 teaspoon of cream of tartar plus 1/4 teaspoon baking soda for 1 teaspoon of baking powder. Source: Emergency Substitutions. Better Homes and Gardens New Cookbook. Des Moines, Ia: Better Homes and Gardens Books, 1999.