* Talc is a mineral that is insoluble in water. It will simply sink to the bottom and form a cloudy suspension.
* Cornstarch is a carbohydrate that will also form a cloudy suspension in water. It may partially dissolve, but it won't fully disappear.
However, baby powder can absorb water and create a thick paste-like consistency. This is why it can be used to absorb moisture and prevent diaper rash.
