Final answer:
The salt solution with a pH of 7.0 at 25 degrees Celsius is most likely NaClO₄, LiF, or RbBr, since these salts originate from the neutralization of strong acids by strong bases and typically lead to neutral solutions, unlike NH₄Cl which would result in an acidic solution due to the hydrolysis of NH₄+.
Step-by-step explanation:
A 0.1 M salt solution has a pH of 7.0 at 25 degrees Celsius, and the question asks which salt (LiF, RbBr, NaClO₄, NH₄Cl) this might be. In order to determine which salt is in the solution, it is necessary to understand the properties of the resulting solution when the salt is dissolved in water. Salts formed from the neutralization of a strong acid by a strong base will produce a neutral solution with pH 7, such as NaCl from HCl and NaOH.
Given that NaClO₄ (sodium perchlorate) is the product of a strong acid (HClO₄) and a strong base (NaOH), it will not affect the pH of the water, leading to a neutral solution, just like NaCl. LiF is formed from the reaction of a strong base (LiOH) with a weak acid (HF), and typically these salts would make the solution slightly basic, but given the properties of F- it is an exception and will also result in a neutral solution. RbBr is similar in behavior to LiF, where RbOH is a strong base and HBr is a strong acid, resulting in a neutral solution. NH₄Cl, on the other hand, is derived from the reaction of a weak base (NH₃) with a strong acid (HCl), leading to a slightly acidic solution due to the hydrolysis of NH₄+.
Therefore, since the salt solution has a pH of 7 and is neutral, we can rule out NH₄Cl, as it would create an acidic solution. The salt in question is more likely NaClO₄ or one of the other salts that form neutral solutions, such as LiF or RbBr. However, the additional context about sodium chloride (NaCl) forming a neutral pH upon complete neutralization at the equivalence point may imply that the salt leading to a pH of 7 here is indeed a similar neutral salt like NaClO₄, LiF, or RbBr.