Video Transcript
The following is an incomplete
table. It shows student observations for
the reaction of silver nitrate with different halide ions. What term should be in the empty
cell of the observation row? (A) Red precipitate, (B) orange
precipitate, (C) blue precipitate, (D) white precipitate, (E) green precipitate.
In this question, we need to
identify which observation is for the reaction of silver nitrate with chloride
ions. During qualitative analysis,
chemists often use aqueous silver nitrate to analyze the composition of a substance
to determine the type of halide ion it contains. Qualitative analysis involves
methods for identifying substances present in chemical samples. These techniques can only reveal if
a certain chemical substance is present, not how much of a chemical substance is in
a sample.
In the chemical test described in
this problem, a student adds an aqueous solution of silver nitrate to samples
containing different halide ions. Scientists can distinguish between
the types of halide ions, because they have different reactions with the silver ions
in the silver nitrate solution.
Let’s clear some space to discuss
the results of these tests. When silver nitrate solution is
added to a sample containing fluoride ions, the fluoride ions do not react with the
silver ions. And no precipitate is formed during
the reaction. However, iodide ions do react with
the silver ions to form a yellow precipitate of silver iodide. Bromide ions also react with silver
ions, but a cream-colored precipitate of silver bromide forms instead.
Finally, chloride ions do react
with silver ions. And the white precipitate silver
chloride is formed. We can see that the color of the
silver chloride precipitate is noticeably different from the color of the silver
bromide and silver iodide precipitates. So, we have determined that the
observation that would be made when silver nitrate is combined with chloride ions is
the formation of a white precipitate.
In conclusion, the term that should
be in the empty cell of the observation row is white precipitate, or answer choice
(D).
