A liquidated damages clause sets an amount in a contract in the event of a breach. A liquidated damages clause isn't a penalty, though it may sound like one. A penalty is usually disproportionate to the actual harm, and is meant to punish or deter breaching a contract.
Acidic stools can be caused from absorption problems from the diet and foods you eat. Some people have acidic stools as a result of a lactose intolerance.
However, black stool can also be caused by a serious condition, such as bleeding in the digestive tract caused by a peptic ulcer. Black stool that is tarry in texture and foul smelling is often a symptom of upper gastrointestinal bleeding from the esophagus, stomach or small intestine. This is called melena.