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Question 15 of 15 ncorrect Sapling Learning macmillan learning A solution contai

ID: 1061799 • Letter: Q

Question

Question 15 of 15 ncorrect Sapling Learning macmillan learning A solution containing a mixture of metal cations was treated as follows. 1. Dilute HCI was added and a precipitate formed. The precipitate was filtered off 2. H2S was bubbled through the acidic solution. No precipitate formed 3. The pH was raised to about 9 and H2S was again bubbled through the solution. A precipitate formed and was filtered off 4. Finally, sodium carbonate was added to the filtered solution and no precipitate formed What can be said about the presence of each of these groups of cations in the original solution? Cation Group Description Present in the original solution? form insoluble chlorides Ag+, Pb2+, Hg22 At least one of these ions was present. Bi3+, Cd 2+ Cu 2+ Hg 2+ form acid-insoluble At least one of these ions was present 2+ 3+ 2+ 4+ sulfides Sb Sn Sn 3+ 2+, Cr3+, Fe 2+ form base-insoluble Co None of these ions were present. sulfides or hydroxides 3+ 2+ 2+ Fe Mn Zn Ba2+, Ca2+, Mg2+. sr2+ form insoluble carbonates None of these ions were present completely soluble Li+, Na*, K*, NH4 unknown All of these ions were present. unknown There is a hint available! At least one of these ions was present View the hint by clicking on the bottom divider bar. Click on the None of these ions were present divider bar again to hide the hint Close Previous Give Up & View Solution Check Answer Next Exit Hint

Explanation / Answer

Cation Group

Description

Present in the original solution

Ag+, Pb2+, Hg22+

Form insoluble chlorides

Atleast one of these ions was present/All of the ions were present.

Ag+ + Cl- ----> AgCl (s, white)

Pb2+ + 2 Cl- ----> PbCl2 (s, white)

Hg22+ + 2 Cl- ----> Hg2Cl2 (s, white)

Bi3+, Cd2+, Cu2+, Hg2+, Pb2+, Sb3+, Sn2+, Sn4+

Form acid-insoluble sulfides

No precipitate was formed. Hence,

None of these ions were present.

Al3+, Co2+, Cr3+, Fe2+, Fe3+, Ni2+, Mn2+, Zn2+

Form base-insoluble sulfides or hydroxides

A precipitate was formed; hence

Atleast one of these ions was present.

The pH was raised to 9. Al3+, Cr3+, Fe2+, Fe3+ can form hydroxides.

Co2+, Ni2+, Mn2+ and Zn2+ can form sulfides.

Ba2+, Ca2+, Mg2+, Sr2+

Form insoluble carbonates

No precipitate was formed. Hence,

None of these ions were present.

Li+, Na+, K+, NH4+

Completely soluble

No particular tests were performed to check for the presence of these ions. Hence,

Unknown

Cation Group

Description

Present in the original solution

Ag+, Pb2+, Hg22+

Form insoluble chlorides

Atleast one of these ions was present/All of the ions were present.

Ag+ + Cl- ----> AgCl (s, white)

Pb2+ + 2 Cl- ----> PbCl2 (s, white)

Hg22+ + 2 Cl- ----> Hg2Cl2 (s, white)

Bi3+, Cd2+, Cu2+, Hg2+, Pb2+, Sb3+, Sn2+, Sn4+

Form acid-insoluble sulfides

No precipitate was formed. Hence,

None of these ions were present.

Al3+, Co2+, Cr3+, Fe2+, Fe3+, Ni2+, Mn2+, Zn2+

Form base-insoluble sulfides or hydroxides

A precipitate was formed; hence

Atleast one of these ions was present.

The pH was raised to 9. Al3+, Cr3+, Fe2+, Fe3+ can form hydroxides.

Co2+, Ni2+, Mn2+ and Zn2+ can form sulfides.

Ba2+, Ca2+, Mg2+, Sr2+

Form insoluble carbonates

No precipitate was formed. Hence,

None of these ions were present.

Li+, Na+, K+, NH4+

Completely soluble

No particular tests were performed to check for the presence of these ions. Hence,

Unknown

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