How might you tell whether or not your toothpaste contained calcium carbonate, #CaCO_3#, or perhaps baking soda, #NaHCO_3#, without looking at the ingredients label?
To tell whether the toothpaste contains any carbonate or bicarbonate, drop a small amount into an acid such as vinegar. Look for bubbles of carbon dioxide.
Here are the chemical equations:
There are other household acids such as most toilet bowl cleaners, but vinegar is safest. Be sure to rinse your container well and wash your hands after the experiment.