Answer: AgCl + Fe
Explanation:
A single replacement reaction is one in which a more reactive element displaces a less reactive element from its salt solution. Thus one element should be different from another element.
A general single displacement reaction can be represented as :

The blanced chemical reaction will be :

Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. ... Salt is essential for life in general, and saltiness is one of the basic human tastes
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Answer is: carbon dioxide (CO₂) can affect the end point of the titration.
Carbon dioxide, or carbon(IV) oxide, reacts with water and form carbonic acid, which can affect the end point of the titration, because more base is needed for neutralization of partially neutralized stomach acid.
Balanced chemical reaction of carbon dioxide and water: CO₂ + H₂O → H₂CO₃.