The titrant in the given scenario is NaOH. The term “titrant” refers to the solution that is added to the unknown solution during a titration. In this case, NaOH is slowly added to react with the analyte, which is HCl.
To understand why NaOH is the titrant and not HCl, let’s first discuss the concept of titration. Titration is a technique used in analytical chemistry to determine the concentration of a substance in a solution. It involves the controlled addition of a solution of known concentration (titrant) to react with the analyte in the unknown solution until a reaction endpoint is reached.
In this particular titration, the unknown solution contains HCl, which needs to be quantitatively determined. The reaction between HCl and NaOH is a classic example of an acid-base titration. HCl is an acid, while NaOH is a base. When they react, they undergo a neutralization reaction, forming water and a salt.
HCl + NaOH → H2O + NaCl
In this reaction, the HCl acts as the analyte, and NaOH acts as the titrant. The titration is performed by slowly adding NaOH to the HCl solution until the equivalence point is reached. The equivalence point is the point at which the stoichiometrically equivalent amounts of acid and base have reacted.
The choice of NaOH as the titrant in this acid-base titration is based on several factors. NaOH is a strong base, meaning it completely dissociates in water, providing a known concentration of hydroxide ions (OH-). This makes it easier to accurately determine the amount of NaOH added and calculate the concentration of HCl in the unknown solution.
Additionally, NaOH is readily available and relatively stable, making it a convenient choice for titrations. Its reactivity with HCl allows for a rapid and well-defined endpoint in the titration, which is crucial for obtaining accurate results.
NaOH is the titrant in this titration because it is added to react with the HCl analyte. The reaction between NaOH and HCl is an acid-base neutralization reaction, and the titration is performed to determine the concentration of HCl in the unknown solution. The choice of NaOH as the titrant is based on its known concentration, reactivity with HCl, and convenience in conducting the titration.