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. \(FeSO_4, SO_2,Fe_2O_3,FeCl_3\)
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 |
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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 |
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Aqueous solution of a salt when treated with \(AgNO_3\) solution gives a white precipitate, which dissolves in \(NH_4OH.\) 
The ion present in the salt is: 
1. \(Cl^-\)
2. \(NO_3^-\)
3. \(I^-\)
4. All the av
Subtopic:  Detection of Anions |
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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. \(CrO(O_2) \)
Subtopic:  Detection of Cations |
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A white precipitate obtained in the analysis of a mixture becomes black on treatment with \(\mathrm{NH_4OH}.\) It may be:

1. \(\mathrm{PbCl_2}\)
2. \(\mathrm{AgCl}\)
3. \(\mathrm{HgCl_2}\)
4. \(\mathrm{Hg_2Cl_2}\)
Subtopic:  Detection of Cations |
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On adding \(KI\) solution in excess to a solution of \(CuSO_4\) we get a precipitate 'P and another liquor M. Select the correct pairs:

1. P is \(Cu_2I_2 \) and M is \(I_2\) solution 
2. P is \(CuI_2 \) and M is \(I_2\) solution 
3. P is \(Cu_2I_2 \) and M is \(KI_3\) solution 
4. P is \(CuI_2 \) and M is \(KI_3\) solution 
Subtopic:  Detection of Anions |
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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 |
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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 |
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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
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Which of the following anion gives colourless gas during preliminary test?
 
(a) \(SO^{2-}_3\)
(b) \(SO^{2-} _4\) 
(c) \(NO^-_2 \)
(d) \(CH_3COO^- \) 

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