Preheat the oven to 230 degrees. In a small bowl, dissolve the yeast and 1 teaspoon of sugar in 1 1/4 cup warm water and vegetable oil. Let stand for about 10 minutes.
In a large bowl, mix flour, 1/2 cup sugar, salt. Make a hollow in the center, add a mixture of oil and yeast. Knead the dough. If the mixture is dry, add a couple tablespoons of water. Knead the dough until smooth, 7 to 8 minutes. Lightly oil a large bowl, put the dough in a bowl and turn over to coat with oil. Cover with cling film and let rise in a warm place until it doubles in size, about 1 hour.
In a large bowl, dissolve the soda in 4 cups of hot water, set aside. Divide the dough into 12 equal parts. Roll out each piece and roll in the shape of a pretzel. After all the dough is in shape, dip each pretzel in an aqueous solution of soda and spread on a flour sprinkled with flour. Sprinkle pretzels with salt. Bake in a preheated oven until browned for about 8 minutes.