Consider the following sequence of tests:
\(M^{n+} ~+ HCl \rightarrow \) White precipitate \(\xrightarrow \Delta \) water soluble
The metal ion \((M^{n+})\)) can be:

1. \(Hg^{2+}\)
2. \(Ag^{+}\) 
3. \(Pb^{2+}\)
4. \(Sn^{2+}\)

Subtopic:  Detection of Cations |
 52%
Level 3: 35%-60%
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Which of the following compounds does magnesium precipitate when you test for it ?

1. \(MgCO_3.MgO \)
2. \(MgCO_3\)
3. \(Mg(OH)_2 \)
4. \(MgNH_4PO_4.6H_2O \)
Subtopic:  Detection of Cations |
 70%
Level 2: 60%+
Hints

Which of the following salts are black ?

(a) \(PbS\) 
(b) \(CuS\)
(c) \(B i _2 S_3 \)
(d) \(HgS\)

1. (a), (b), (c)
2. (b) and (c) 
3. (a), (b), (d)
4. None of the above
Subtopic:  Detection of Cations |
 73%
Level 2: 60%+
Hints

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Which of the following anions gives colourless gas during the preliminary test?
(a) \(SO^{2-}_3\)
(b) \(SO^{2-} _4\) 
(c) \(NO^-_2 \)
(d) \(CH_3COO^- \) 

1. (a), (b) and (d)
2. (b) and (c) 
3. (a), (b) and (c)
4. None of the above
Subtopic:  Detection of Anions | Detection of extra elements |
 70%
Level 2: 60%+
Hints

Which of the following cations precipitate as their chlorides? 

(a) \(Pb^{2+}\)
(b) \(Ag^{+}\)
(c) \(Hg^{2+}_2\)
(d) \(Cd^{2+}\) 

1. (a), (b), (d)
2. (b) and (c) 
3. (a), (b), (c)
4. None of the above
Subtopic:  Detection of Cations |
 75%
Level 2: 60%+
Hints

A white sublimable solid, when boiled with an \(NaOH\) solution, gives a colourless gas that turns Nessler's reagent brown. The solid, on being heated with solid \(K_2Cr_2O_7\) and concentrated \(H_2SO_4,\) gives red brown vapours. The white solid can be :

(a) \(NH_4I\)
(b) \(NH_4Br\)
(c) \(NH_4Cl\)
(d) \((NH_4)_2SO_4\) 

1. (a), (b), (d)
2. (b) and (c) 
3. (a), (b), (c)
4. None of the above
Subtopic:  Detection of Cations |
 54%
Level 3: 35%-60%
Hints

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The cation which gives yellow ppt with \(K_2CrO_4 \) in acetic acid is:

(a) \(Ba^{2+}\)
(b) \(Pb^{2+}\)
(c) \(Ca^{2+}\)
(d) \(Al^{3+}\)

1. (a) and (b)
2. (b) and (c) 
3. (a), (b) and (c)
4. (a), (b), (c) and (d)
Subtopic:  Detection of Cations |
Level 3: 35%-60%
Hints

On reaction with dilute \(H_2SO_4,\) which of the following salts will give out a gas that turns an acidified dichromate paper green?

(a) \(Na_2CO_3\)
(b) \(Na_2S\)
(c) \(ZnSO_3\)
(d) \(FeS\)

1. (b), (c), (d)
2. (b) and (c) 
3. (a), (b), (c)
4. None of the above
 
 
Subtopic:  Detection of Cations |
 64%
Level 2: 60%+
Hints

Which of the following cations cannot be separated by passing \(H_2S\) through their solutions to which \(NH_4OH\) has been added?
(a) \(Ca^{2+}\) and \(Ni^{2+}\)
(b) \(Mg^{2+}\) and \(Mn^{2+}~\)
(c) \(Ni^{2+}\) and \(Mn^{2+}\)
(d) \(Co^{2+}\) and \(Zn^{2+}\)

1. (a), (b), (d)
2. (c) and (d) 
3. (a), (b), (c)
4. (b) Only
Subtopic:  Detection of Cations |
 64%
Level 2: 60%+
Hints

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Incorrect statements among the following are:
(a) Group I radicals are precipitated as chloride
(b) Group IV radicals are precipitated as sulphide
(c) Group V radicals are precipitated as hydroxide
(d) Group III radicals are precipitated as chloride
1. (a), (b) and (d)
2. (c) and (d) 
3. (a), (b) and (c)
4. (a), (b), (c) and (d)
Subtopic:  Detection of Cations |
 61%
Level 2: 60%+
Hints