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Is it necessary to acidify a solution be...

Is it necessary to acidify a solution before group II cations are precipitated with `H_(2)S`?

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**Step-by-Step Solution:** 1. **Identify Group II Cations**: The Group II cations include copper (Cu²⁺), mercury (Hg²⁺), lead (Pb²⁺), cadmium (Cd²⁺), bismuth (Bi³⁺), and antimony (Sb³⁺). 2. **Understand the Precipitation Process**: The precipitation of Group II cations occurs when hydrogen sulfide (H₂S) is added to a solution containing these cations. ...
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Three separate samples of a solution of a single salt gave these results. One formed a white precipitate with excess ammonia solution, one formed a white precipitate with dil. NaCl solution and one formed a black precipitate with H_(2)S . The salt could be

Which of the following cations form(s) black precipitate(s) with H_(2)S (g) ?

(i) A white solid mixture of two salts containing a common cations in insoluble in water. It dissolves in dilute HCl producing some gases (with effervescence) that turn an acidified dichromate solution gren. After the gases are passed through the acidified dichromate solution, the emerging gas turns baryta water milky. (ii) On treatment with dilute HNO_(3) , the white solid gives a solution which does not directly give a precipitate with a BaCl_(2) solution but gives a white precipitate when warmed with H_(2)O_(2) and then treated with a BaCl_(2) solution. (iii) The solution of the mixture in dilute HCl, when treated with NH_(4)Cl,NH_(4)OH and an Na_(2)HPO_(4) solution, gives a white precipitate. Q. The white precipitate obtained in (ii) indicates the presence of a:

(i) A white solid mixture of two salts containing a common cations in insoluble in water. It dissolves in dilute HCl producing some gases (with effervescence) that turn an acidified dichromate solution gren. After the gases are passed through the acidified dichromate solution, the emerging gas turns baryta water milky. (ii) On treatment with dilute HNO_(3) , the white solid gives a solution which does not directly give a precipitate with a BaCl_(2) solution but gives a white precipitate when warmed with H_(2)O_(2) and then treated with a BaCl_(2) solution. (iii) The solution of the mixture in dilute HCl, when treated with NH_(4)Cl,NH_(4)OH and an Na_(2)HPO_(4) solution, gives a white precipitate. Q. The white precipitate obtained in (iii) consists of:

(i) A white solid mixture of two salts containing a common cations in insoluble in water. It dissolves in dilute HCl producing some gases (with effervescence) that turn an acidified dichromate solution gren. After the gases are passed through the acidified dichromate solution, the emerging gas turns baryta water milky. (ii) On treatment with dilute HNO_(3) , the white solid gives a solution which does not directly give a precipitate with a BaCl_(2) solution but gives a white precipitate when warmed with H_(2)O_(2) and then treated with a BaCl_(2) solution. (iii) The solution of the mixture in dilute HCl, when treated with NH_(4)Cl,NH_(4)OH and an Na_(2)HPO_(4) solution, gives a white precipitate. Q. The gases evolved in (i) are:

Which of the following cation does not give precipitate with H_(2)S in neutral medium?

In equalitative analysis, cations of graph II as well as group IV both are precipitated in the form of sulphides. Due to low value of K_(sp) of group II sulphides, group reagent is H_(2)S in the presence of dil. HC1 , and due to high value of K_(sp) of group IV sulphides, group reagent is H_(2)S in the presence of NH_(4)OH and NH_(4)C1 . In a solution containing 0.1M each of Sn^(2+), Cd^(2+) , and Ni^(2+) ions, H_(2)S gas is passed. K_(sp) of SnS = 8 xx 10^(-29), K_(sp) of CdS = 15 10^(-28), K_(sp) of NiS - 3 xx 10^(-21), K_(1) of H_(2)S = 1 xx 10^(-7), K_(2) of H_(2)S = 1 xx 10^(-14) At what value of pH, NiS will start to precipitate?

In equalitative analysis, cations of graph II as well as group IV both are precipitated in the form of sulphides. Due to low value of K_(sp) of group II sulphides, group reagent is H_(2)S in the presence of dil. HC1 , and due to high value of K_(sp) of group IV sulphides, group reagent is H_(2)S in the presence of NH_(4)OH and NH_(4)C1 . In a solution containing 0.1M each of Sn^(2+), Cd^(2+) , and Ni^(2+) ions, H_(2)S gas is passed. K_(sp) of SnS = 8 xx 10^(-29), K_(sp) of CdS = 15 10^(-28), K_(sp) of NiS - 3 xx 10^(-21), K_(1) of H_(2)S = 1 xx 10^(-7), K_(2) of H_(2)S = 1 xx 10^(-14) Which of the following sulphides is more soluble in pure water?

In equalitative analysis, cations of graph II as well as group IV both are precipitated in the form of sulphides. Due to low value of K_(sp) of group II sulphides, group reagent is H_(2)S in the presence of dil. HC1 , and due to high value of K_(sp) of group IV sulphides, group reagent is H_(2)S in the presence of NH_(4)OH and NH_(4)C1 . In a solution containing 0.1M each of Sn^(2+), Cd^(2+) , and Ni^(2+) ions, H_(2)S gas is passed. K_(sp) of SnS = 8 xx 10^(-29), K_(sp) of CdS = 10^(-28), K_(sp) of NiS - 3 xx 10^(-21) K_(1) of H_(2)S = 1 xx 10^(-7), K_(2) of H_(2)S = 1 xx 10^(-14) If 0.1M HC1 is mixed in the solution containing only 0.1 M Cd^(2+) ions and saturated with H_(2)S , then [Cd^(2+)] remaining in the solution after CdS stopes to precipitate is:

In equalitative analysis, cations of graph II as well as group IV both are precipitated in the form of sulphides. Due to low value of K_(sp) of group II sulphides, group reagent is H_(2)S in the presence of dil. HC1 , and due to high value of K_(sp) of group IV sulphides, group reagent is H_(2)S in the presence of NH_(4)OH and NH_(4)C1 . In a solution containing 0.1M each of Sn^(2+), Cd^(2+) , and Ni^(2+) ions, H_(2)S gas is passed. K_(sp) of SnS = 8 xx 10^(-29), K_(sp) of CdS = 15 10^(-28), K_(sp) of NiS - 3 xx 10^(-21), K_(1) of H_(2)S = 1 xx 10^(-7), K_(2) of H_(2)S = 1 xx 10^(-14) If H_(2)S is passed into the above mixture in the presence of HC1 , which ion will be precipitated first?

CENGAGE CHEMISTRY ENGLISH-QUALITATIVE INORGANIC SALT ANALYSIS-Viva Voce Questions And Part-C (Analysis Of Cations)
  1. Why are only Pb^(2+),Ag^(o+) and Hg(2)^(2+) ions precipitated in group...

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  2. Why is lead placed in group I as well in II?

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  3. Is it necessary to acidify a solution before group II cations are prec...

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  4. Give the reason for the formation of a light yellow or white ppt. in t...

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  5. Why do we Prefer HCl for preparing solution of cations?

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  6. Is it advisable to use conc. HCI in place of dilute HCI for preparing ...

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  7. Why is it essential to boil off H(2)S gas before proceeding to group I...

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  8. Can the solution be acidified with HNO(3) in group II before passing H...

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  9. What can it be, if the precipitate of group I is soluble in hot water ...

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  10. Why do we not prefer to prepare original solution of cations in conc....

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  11. Group I filtrate is made moderately acidic before proceeding to group ...

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  12. Why do we add excess of NH(4)Cl and NH(4)OH in the precipitation of gr...

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  13. Why do we add excess of NH(4)Cl and NH(4)OH in the precipitation of gr...

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  14. Why is it essential to oxidise ferrous salt to ferric salt in group II...

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  15. Can NH(4)Cl be replaced by any other ammonium salt for the precipitati...

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  16. How will you distinguish between ferrous and ferric salts?

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  17. Can we add NH(4)OH first and NH(4)Cl later in the analysis of group II...

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  18. Can we use NaCla and NaOH in place of Na(4)Cl and NH(4)OH in the group...

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  19. Why are Zn,MnNi,Co not precipitated n the group III as hydroxides?

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  20. Why are the group IV cations not precipitated as sulphides on passing ...

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