\(Cu^{2+}\) 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 |
Please attempt this question first.
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. \(Ca^{2+}\)
Subtopic:  Detection of Cations |
 51%
Please attempt this question first.
Hints

A metal nitrate reacts with \(Kl \) to give a black precipitate which upon additionof excess
of \(Kl\) 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 |
Please attempt this question first.
Hints

advertisementadvertisement

The reagents, \(NH_4Cl\) and aqueous \(NH_3\), will precipitate:

1. \(Ca^{2+}\)
2. \(Al^{3+}\)
3. \(B i^{3+}\)
4. \(Mg^{2+} \)
Subtopic:  Detection of Cations |
 69%
Please attempt this question first.
Hints

Which of the following reagents can be used to distinguish between sulphite and sulphate ions present in a solution?
1. \(FeSO_4\)
2. \(Na_2[FeI(CN)_5NO] \)
3. \(BaCl_2 \)
4. \(Na_3[Co(NO_2)6] \)
Subtopic:  Detection of Anions |
Please attempt this question first.
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 
Subtopic:  Detection of Cations |
Please attempt this question first.
Hints

advertisementadvertisement

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 |
Please attempt this question first.
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 |
Please attempt this question first.
Hints

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 |
 72%
Please attempt this question first.
Hints

advertisementadvertisement

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 |
 72%
Please attempt this question first.
Hints