Why pb²+ come in both first and second group ?
Answers
Answer:
As we know that, first group is precipitated in the form of chlorides in the presence of dilute HCl and second group is precipitated in the form of sulphides in the presence of hydrogen sulphide gas (which is passes in the solution in the presence of dilute HCl).
Also, groups in cation analysis are on the basis of solubility product.
Now, Lead ion precipitated in the form of lead chloride, which has poor solubility.
Also, lead ion precipitated in the form of lead sulphide, which also has poor solubility.
Another correct reason is that lead cannot be precipitated completely by HCl in the first group, so it is placed in both the groups.
Explanation:
Hey, here is ur answer
The metal ions remaining in solution are precipitated as insoluble lead sulphide on passing H2S into the filtrate (in the 2nd group). In the 1st group lead is expected to get precipitated as lead(II) chloride. ... Since lead is not completely precipitated by HCl in the 1st group, it is placed in both the groups.
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