How much baking soda is requierd to make 50ml of saturated solution at room tempurture?

Well, darling, to make a saturated solution of baking soda at room temperature, you'll need about 7.8 grams of baking soda for every 50 ml of water. Just make sure to stir it well until no more baking soda can dissolve, and voilà, you've got yourself a saturated solution! Just don't go overboard and end up with a gritty mess.