Which pair of ions can be distinguished using a flame test in the school laboratory?
A - HSC - SSCE Chemistry - Question 5 - 2022 - Paper 1
Question 5
Which pair of ions can be distinguished using a flame test in the school laboratory?
A. Ag<sup>+</sup> and Mg<sup>2+</sup>
B. Ba<sup>2+</sup> and Ca<sup>2+</sup> ... show full transcript
Worked Solution & Example Answer:Which pair of ions can be distinguished using a flame test in the school laboratory?
A - HSC - SSCE Chemistry - Question 5 - 2022 - Paper 1
Step 1
A. Ag<sup>+</sup> and Mg<sup>2+</sup>
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Answer
When subjected to a flame test, Ag<sup>+</sup> gives a characteristic blue-white flame, while Mg<sup>2+</sup> does not produce a definitive color that can be distinguished.
Step 2
B. Ba<sup>2+</sup> and Ca<sup>2+</sup>
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Ba<sup>2+</sup> produces a green flame, while Ca<sup>2+</sup> produces an orange-red flame. Therefore, these ions can be distinguished using a flame test.
Step 3
C. Br<sup>-</sup> and Cl<sup>-</sup>
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Answer
Neither Br<sup>-</sup> nor Cl<sup>-</sup> produces distinct flame colors when subjected to a flame test, so they cannot be distinguished in this manner.
Step 4
D. Fe<sup>2+</sup> and Fe<sup>3+</sup>
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Answer
Fe<sup>2+</sup> emits a light green or bluish-green flame, while Fe<sup>3+</sup> produces a more yellowish flame. Thus, these ions can be distinguished.
