A. Cu
B. Cr
C. Ni
D. Al
¨ The borax bead test is a common qualitative test used in analytical chemistry to identify the presence of certain metal ions. It involves heating a small amount of borax (sodium borate) in a flame until it forms a bead, which is then dipped into a solution containing the metal ion being tested. The bead is then reheated in the flame and observed for a characteristic color.
¨ Copper (Cu), chromium (Cr), and nickel (Ni) are all metals that can form colored borax beads under certain conditions. Copper forms a green bead, chromium forms a green bead in the oxidizing flame and a red bead in the reducing flame, and nickel forms a grayish-white or light brown bead.
¨ However, aluminum (Al) does not give a characteristic borax bead test because it forms an amorphous, colorless bead that does not exhibit any distinctive color. Therefore, option (D) Al (Aluminum) is the correct answer.
Submitted by :- Jamil Ahmed