A student is given a sample in lab which contains one of the ions listed below. After adding a few drops ofsolution to part of the unknown sample, the student got a greyish precipitate. After adding a few drops ofsolution to another part of the unknown sample the student got a black precipitate. Based on these observations the only possible ion in this student’s sample is:
a. F-
b. C2H3O2-
c. SO4 2-
d. S2 -
e. Cl-
Someone help me please,
A student is given a sample in lab which contains one of the ions listed below. After adding a few drops of AgNo3 solution to part of the unknown sample, the student got a greyish precipitate. After adding a few drops of Mg(NO3)2 solution to another part of the unknown sample the student got a black precipitate. Based on these observations the only possible ion in this student’s sample is:
Sorry the question is second one
is it S 2- or sulfide
The problem doesn't make sense to me and I'm an analytical chemist. Ag2S is black to black/brown and MgS is soluble. The only ions that will form any kind of ppt with AgNO3 (from those listed) is AgCl (white), Ag2S (black). Of those two, Mg(NO3)2 will not form ANY ppt (much less a black one), with either. Maybe I've missed something.
Can u please
explain in much detail, i could not find the answer
To determine the possible ion in the student's sample based on the observations, we need to understand the chemistry behind the formation of precipitates with different ions.
The greyish precipitate suggests the presence of a silver ion (Ag+). Silver chloride (AgCl) is a white precipitate, but it can darken over time to appear greyish. Therefore, the presence of a greyish precipitate indicates the possible presence of Cl- ions.
The black precipitate suggests the formation of a black compound, which is often associated with the formation of a sulfide. In this case, the presence of a black precipitate points to the possible presence of S2- ions.
Looking at the options given:
a. F-: Fluoride ions (F-) do not form greyish or black precipitates; we can eliminate this option.
b. C2H3O2-: Acetate ions (C2H3O2-) do not form greyish or black precipitates; we can eliminate this option.
c. SO4 2-: Sulfate ions (SO4 2-) do not form black precipitates; we can eliminate this option.
d. S2 -: The formation of a black precipitate is consistent with the presence of sulfide ions (S2-). This is a possibility.
e. Cl-: The formation of a greyish precipitate is consistent with the presence of chloride ions (Cl-). This is also a possibility.
Based on the observations, the only possible ion in the student's sample is either d. S2 - or e. Cl-.