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Q. No.\(Cu^{2+}\) ions can be reduced to \(Cu^{+}\) ions by the addition of an aqueous solution of:
1. \(KF \)
2. \(KCl \)
3. \(KI \)
4. \(KOH \)
Subtopic: Detection of Cations | Detection of Anions |
64%
Level 2: 60%+
Hints
A basic radical among the following that cannot be precipitated by
\(H_2S \) gas in the presence of \(NH_3 \) is:
1. \(Mn^{2+}\)
2. \(Ni^{2+}\)
3. \(Cd^{2+}\)
4. \(Ca^{2+}\)
\(H_2S \) gas in the presence of \(NH_3 \) is:
1. \(Mn^{2+}\)
2. \(Ni^{2+}\)
3. \(Cd^{2+}\)
4. \(Ca^{2+}\)
Subtopic: Detection of Cations |
63%
Level 2: 60%+
Hints
A metal nitrate reacts with \(KI\) to give a black precipitate which upon addition of excess
of \(KI\) converts into orange colour solution. The cation of the metal nitrate is:
1. \(Hg^{2+}\)
2. \(Bi^{3+}\)
3. \(Pb^{2+}\)
4. \(Cu^+\)
of \(KI\) converts into orange colour solution. The cation of the metal nitrate is:
1. \(Hg^{2+}\)
2. \(Bi^{3+}\)
3. \(Pb^{2+}\)
4. \(Cu^+\)
Subtopic: Detection of Cations |
Level 3: 35%-60%
Hints
Which of the following reagents can be used to distinguish between sulphite and sulphate ions present in a solution?
1. FeSO₄
2. Na₂[Fe(CN)₅NO]
3. BaCl₂
4. Na₃[Co(NO₂)₆]
Subtopic: Detection of Anions |
Level 3: 35%-60%
Hints
\(Na_2CO_3 \) cannot be used in place of \((NH_4)_2CO_3 \) for the precipitation of fifth group radicals.
This is because:
1. Magnesium will precipitate
2. The concentration of carbonate ions is very low
3. Sodium ions will react with acidic radicals
4. \(Na^{+} \) ions interfere with the detection of the fifth group
This is because:
1. Magnesium will precipitate
2. The concentration of carbonate ions is very low
3. Sodium ions will react with acidic radicals
4. \(Na^{+} \) ions interfere with the detection of the fifth group
Subtopic: Detection of Cations |
Level 4: Below 35%
Hints
A metal sulphate (A) on heating evolves two gases (B) and (C) and an oxide (D).
Gas (B) turns \(K_2Cr_2O_7\) paper green while gas (C) forms a trimer in which there
is no \(S-S\) bond. Oxide (D) with conc. \(HCl\) forms a Lewis acid (E) which exists
in a dimer. Compounds (A), (B), (C), (D) and (E), respectively, are:
1. \(FeSO_4, SO_2, SO_3, Fe_2O_3,FeCl_3\)
2. \(Al_2(SO_4)_3,SO_2,SO_3,Al_2O_3,FeCl_3\)
3. \(FeS,SO_2,SO_3,FeSO_4,FeCl_3\)
4. \(FeS,SO_2,SO_3,Fe_2(PO_4)_3,FeCl_2\)
Gas (B) turns \(K_2Cr_2O_7\) paper green while gas (C) forms a trimer in which there
is no \(S-S\) bond. Oxide (D) with conc. \(HCl\) forms a Lewis acid (E) which exists
in a dimer. Compounds (A), (B), (C), (D) and (E), respectively, are:
1. \(FeSO_4, SO_2, SO_3, Fe_2O_3,FeCl_3\)
2. \(Al_2(SO_4)_3,SO_2,SO_3,Al_2O_3,FeCl_3\)
3. \(FeS,SO_2,SO_3,FeSO_4,FeCl_3\)
4. \(FeS,SO_2,SO_3,Fe_2(PO_4)_3,FeCl_2\)
Subtopic: Detection of Cations |
52%
Level 3: 35%-60%
Hints
In this sequence, X, Y, Z are, respectively:
| 1. | Acidified \(H_2O_2;\) Alkaline \(H_2O_2;\) Acidified \(H_2O_2\) |
| 2. | Alkaline \(H_2O_2;\) Acidified \(H_2O_2;~Zn/HCl.\) |
| 3. | Acidified \(H_2O_2;\) Heat; Alkaline \(H_2O_2\) |
| 4. | Alkaline \(H_2O_2;\) Acidified \(H_2O_2;\) on standing |
Subtopic: Detection of Cations |
Level 3: 35%-60%
Hints
A white salt is insoluble in cold water but soluble in boiling water.
Its solution when treated with potassium chromate solution
gives a yellow precipitate. The salt may be:
1. \(BaCl_2 \)
2. \(SrCl_2 \)
3. \(PbCl_2\)
4. \(Hg(NO_3)_2\)
Its solution when treated with potassium chromate solution
gives a yellow precipitate. The salt may be:
1. \(BaCl_2 \)
2. \(SrCl_2 \)
3. \(PbCl_2\)
4. \(Hg(NO_3)_2\)
Subtopic: Detection of Cations | Detection of Anions |
67%
Level 2: 60%+
Please attempt this question first.
Hints
A white powder when strongly heated gives off brown fumes. Aqueous solution of this powder gives a yellow precipitate with a solution of \(KI\). When a solution of barium chloride is added to a solution of this powder, a white precipitate results. This white powder may be:
1. A soluble sulphate
2. \(KBr \) and \(NaBr \)
3. \(Ba(NO_3)_2\)
4. \(AgNO_3\)
1. A soluble sulphate
2. \(KBr \) and \(NaBr \)
3. \(Ba(NO_3)_2\)
4. \(AgNO_3\)
Subtopic: Detection of Cations | Detection of Anions |
53%
Level 3: 35%-60%
Please attempt this question first.
Hints
Ammonium dichromate is used in some fireworks. The green-coloured powder blown in the air is due to:
1. \(CrO_3 \)
2. \(Cr_2O_3 \)
3. \(Cr\)
4. \(CrO(O_2) \)
1. \(CrO_3 \)
2. \(Cr_2O_3 \)
3. \(Cr\)
4. \(CrO(O_2) \)
Subtopic: Detection of Cations |
77%
Level 2: 60%+
Hints
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