Preheat oven to 350 degrees.
In a medium bowl with wire whisk or spoon, stir flour, cocoa, baking powder, and 1 1/4 cups sugar until thoroughly blended. With the same wire whisk or spoon, stir in water, salad oil, vanilla, liquor, and egg yolks until smooth.
In a large bowl with mixer at high speed, beat egg whites and cream of tartar until a soft peak forms; beating at high speed, gradually sprinkle 1/2 cup sugar, 2 tablespoons of water at a time; beat until sugar is completely dissolved and whites stand at a stiff peak. Do not scrape the sides of the bowl during beating.
With rubber spatula, gently fold flour mixture into beaten egg whites until just blended. Pour batter into ungreased 10 inch tube pan.
Bake for 1 hour or until the top springs back when lightly touched by the finger tip. Invert cake pan on funnel or bottle. Cool completely in the pan. With spatula, loosen the cake from the pan.
Place on cake plate. Sprinkle cake gently with confectioner’s sugar.