Question

A sample of a solid labeled as NaCl may be impure. A student analyzes the sample and determines that it contains 75 percent chlorine by mass. Pure NaCl(s) contains 61 percent chlorine by mass. Which of the following statements is consistent with the data? (I know the answer is d but can someone plz explain to me why? Tyy)

a) The sample contains only NaCl(s).
b) The sample contains NaCl(s) and NaI(s).
c) The sample contains NaCl(s) and KCl(s).
d) The sample contains NaCl(s) and LiCl(s).

Answer 1

Answer:

the correct and answer is C

Answer 2

The statement D is consistent with the data.

• The percentage of chlorine by mass present in the sample of NaCl is to be increased.
• In order to do so we need to add such a compound to the sample which has more percentage of chlorine by mass than that present in NaCl.
• This is to be done because the percentage of chlorine will increase only if the increase in the mass of chlorine in the mixture results in lesser increase in the mass of the mixture.
• Since Li is lighter than Na , LiCl has higher chlorine percentage by mass than NaCl , so its addition will result in the increase in the percentage of chlorine in the mixture.