Baking Powder (Best Option)
3 teaspoons baking powder per 1 teaspoon baking sodaBaking powder contains both an acid and a base, so it leavens by releasing carbon dioxide when moistened and heated, similar to baking soda but without needing an external acid. This makes it the most straightforward substitute in scones, which often have acidic components like buttermilk or cream.
To use baking powder successfully, increase the amount to about three times the baking soda called for, as baking powder is less potent. Watch for a slightly different texture; scones may be a bit softer and less crisp on the edges.
Compared to baking soda, baking powder produces a more balanced rise without the metallic or soapy aftertaste that can occur if baking soda is not neutralized by acid. The final scones will be tender and well-leavened, though the flavor may be less sharp.