Not quite. Pure baking soda (sodium bicarbonate) contains no acid, unlike baking powder. That acid is necessary for the soda to release carbon dioxide during baking and make the batter rise.
If you simply replace baking powder with pure baking soda, that acid is missing from the batter. You need to add it yourself – for example with buttermilk, yogurt, lemon juice, or vinegar. Without enough acid, less CO₂ forms, and the batter rises less.
You also need to be careful with the amount: replacing baking powder one-to-one with baking soda usually means far more soda in the batter than the available acid can neutralize. The excess, still-alkaline soda then remains partly unreacted in the baked goods – which causes the well-known soapy-bitter aftertaste sometimes noticed with incorrect dosing.