Inorganic Semimicro analysis for Double mixture salts Procedure (as video urls and Flow charts )
Model Practical Exam Viva Questions
Viva-voce https://youtu.be/Z4de4u1TqAc?si=1gJTH2jxYiYu1H5M
1. Which of the following reagents is used to precipitate Group I cations? a) Dilute HCl b) Concentrated HCl c) Dilute H₂SO₄ d) Dilute HNO₃ Answer: b) Concentrated HCl Explanation: Group I cations (Pb²⁺, Hg₂²⁺, Ag⁺) are insoluble in concentrated HCl.
2. What is the characteristic color of the precipitate formed when H₂S gas is passed through a solution containing Pb²⁺ ions in acidic medium? a) Black b) White c) Yellow d) Brown Answer: a) Black Explanation: PbS is a black precipitate.
3. Which of the following cations belong to Group IIA? a) Cu²⁺, Bi³⁺, Cd²⁺ b) As³⁺, Sb³, Sn⁴⁺ c) Fe³⁺, Al³⁺, Cr³⁺ d) Zn²⁺, Mn²⁺, Ni²⁺ Answer: a) Cu²⁺, Bi³⁺, Cd²⁺ Explanation: Group IIA cations form sulfides insoluble in acidic medium but soluble in yellow ammonium sulfide.
4. How is Fe³⁺ ion confirmed in solution? a) By adding KSCN solution b) By adding NH₄OH solution c) By adding BaCl₂ solution d) By adding NaOH solution Answer: a) By adding KSCN solution Explanation: Fe³⁺ ions react with KSCN to form a blood-red complex of [Fe(SCN)]²⁺.
5. Which group of cations is precipitated by passing H₂S gas through an alkaline solution? a) Group I b) Group II c) Group III d) Group IV Answer: c) Group III Explanation: Group III cations (Fe³⁺, Al³⁺, Cr³⁺) form sulfides insoluble in alkaline medium.
6. What is the color of the precipitate formed when NH₄OH is added to a solution containing Ni²⁺ ions? a) Blue b) Green c) Brown d) White Answer: b) Green Explanation: Ni²⁺ ions form a green precipitate of Ni(OH)₂ with NH₄OH.
7. Which reagent is used to separate Al³⁺ from Fe³⁺ in Group III? a) NaOH b) NH₄OH c) HCl d) H₂SO₄ Answer: a) NaOH Explanation: Al(OH)₃ is amphoteric and dissolves in excess NaOH to form [Al(OH)₄]⁻, while Fe(OH)₃ is insoluble.
8. Which cation in Group IV gives a characteristic green flame test? a) Ba²⁺ b) Sr²⁺ c) Ca²⁺ d) Mg²⁺ Answer: a) Ba²⁺ Explanation: Ba²⁺ ions impart a green color to the flame.
9. Which reagent is used to confirm the presence of NH₄⁺ ions in a salt? a) NaOH b) HCl c) H₂SO₄ d) HNO₃ Answer: a) NaOH Explanation: NaOH liberates NH₃ gas with a characteristic pungent odor when heated with ammonium salts.
10. Which of the following is NOT a characteristic of semi-micro analysis? a) Use of small quantities of reagents b) Use of micro test tubes c) Use of large volumes of solutions d) Use of spot plates Answer: c) Use of large volumes of solutions Explanation: Semi-micro analysis emphasizes the use of minimal quantities of reagents and solutions.
Chloride, carbonate,
chromate, sulfate, and nitrate (1-5)
1. Q: How do you detect the presence of chloride ions in a solution?
A: By adding AgNO3 and observing a white precipitate of AgCl.
2. Q: What is the purpose of adding phenolphthalein indicator in the analysis of carbonate ions?
A: To indicate the presence of carbonate ions by turning pink.
3. Q: How do you differentiate between chromate and dichromate ions?
A: By adding a reducing agent, such as ethanol, which reduces dichromate to chromate.
4. Q: What is the effect of adding BaCl2 to a solution containing sulfate ions?
A: A white precipitate of BaSO4 forms.
5. Q: How do you detect the presence of nitrate ions in a solution?
A: By adding Cu and concentrated H2SO4, which produces a blue color.
Phosphate, silicate,
borate, fluoride, and iodide (6-10)
6. Q: What is the purpose of adding ammonium molybdate to a solution containing phosphate ions?
A: To form a yellow precipitate of ammonium phosphomolybdate.
7. Q: How do you detect the presence of silicate ions in a solution?
A: By adding ammonium chloride and observing a white precipitate of silicon dioxide.
8. Q: What is the effect of adding HCl to a solution containing borate ions?
A: A white precipitate of boric acid forms.
9. Q: How do you detect the presence of fluoride ions in a solution?
A: By adding calcium chloride and observing a white precipitate of calcium fluoride.
10. Q: What is the purpose of adding chlorine water to a solution containing iodide ions?
A: To oxidize iodide ions to iodine, which forms a brown color.
Cyanide, thiocyanate,
arsenate, arsenite, and antimonate (11-15)
11. Q: What is the effect of adding FeSO4 to a solution containing cyanide ions?
A: A blue precipitate of Prussian blue forms.
12. Q: How do you detect the presence of thiocyanate ions in a solution?
A: By adding FeCl3 and observing a red color.
13. Q: What is the purpose of adding silver nitrate to a solution containing arsenate ions?
A: To form a yellow precipitate of silver arsenate.
14. Q: How do you differentiate between arsenate and arsenite ions?
A: By adding silver nitrate, which forms a yellow precipitate with arsenate but not with arsenite.
15. Q: What is the effect of adding hydrogen sulfide to a solution containing antimonate ions?
A: A yellow precipitate of antimony sulfide forms.
Oxalate, tartrate,
citrate, succinate, and adipate (16-20)
16. Q: What is the purpose of adding calcium chloride to a solution containing oxalate ions?
A: To form a white precipitate of calcium oxalate.
17. Q: How do you detect the presence of tartrate ions in a solution?
A: By adding potassium acetate and observing a white precipitate of potassium tartrate.
18. Q: What is the effect of adding copper sulfate to a solution containing citrate ions?
A: A blue precipitate of copper citrate forms.
19. Q: How do you differentiate between succinate and adipate ions?
A: By adding a solution of potassium permanganate, which oxidizes succinate but not adipate.
20. Q: What is the purpose of adding silver nitrate to a solution containing adipate ions?
A: To form a white precipitate of silver adipate.
Group Seperation
Flow Charts of Group Analysis of Certain Groups of Cations (Note: Dont confuse yourself and compare the procedure with the flow chart. Select any one flow chart which suits best for you)
Flowcharts for Cation Group Analysis
Here are simplified flowcharts for the analysis of cations in Groups I to VI. Note that these are general outlines and specific procedures may vary depending on the exact cations present in the mixture.
Group I: Ag+, Hg22+, Pb2+
- Reagent: Dilute HCl
- Precipitate: White ppt. of AgCl, Hg2Cl2, PbCl2
- Confirmation Tests:
- Ag+: Dissolve ppt. in hot water, add K2CrO4 → Red ppt. of Ag2CrO4
- Hg22+: Treat ppt. with NH4OH → Black ppt. of Hg and HgNH2Cl
- Pb2+: Dissolve ppt. in hot water, add K2CrO4 → Yellow ppt. of PbCrO4
Group II: Hg2+, Pb2+, Cu2+, Bi3+, Cd2+, As3+, Sb3+, Sn2+
- Reagent: H2S in acidic medium (dil. HCl)
- Precipitate: Black or colored ppt. of sulfides
- Subgroups:
- Subgroup IIA: HgS (black), PbS (black), CuS (black), Bi2S3 (brown), CdS (yellow)
- Subgroup IIB: As2S3 (yellow), Sb2S3 (orange), SnS2 (yellow)
- Separation: Based on solubility in (NH4)2S or KOH
- Confirmation Tests: Various tests involving color reactions, redox reactions, and complex formation
Group III: Al3+, Cr3+, Fe3+
- Reagent: NH4Cl + NH4OH
- Precipitate: White or colored ppt. of hydroxides
- Confirmation Tests:
- Al3+: Dissolve ppt. in NaOH, then add NH4Cl → White ppt. of Al(OH)3
- Cr3+: Fuse ppt. with Na2CO3, extract with water, add H2O2 and H2SO4 → Blue solution of Cr2O72-
- Fe3+: Dissolve ppt. in HCl, add KSCN → Blood-red color due to Fe(SCN)3
Group IV: Zn2+, Mn2+, Co2+, Ni2+
- Reagent: H2S in alkaline medium (NH4Cl + NH4OH)
- Precipitate: Black or colored ppt. of sulfides
- Confirmation Tests:
- Zn2+: Dissolve ppt. in HCl, add K4[Fe(CN)6] → Green ppt. of Zn2[Fe(CN)6]
- Mn2+: Fuse ppt. with Na2CO3 + KNO3, extract with water, add H2O2 and HNO3 → Purple color due to MnO4-
- Co2+: Dissolve ppt. in HCl, add KSCN → Blue solution of Co(SCN)42-
- Ni2+: Dissolve ppt. in HCl, add dimethylglyoxime → Red ppt. of Ni(DMG)2
Group V: Ba2+, Ca2+, Sr2+
- Reagent: (NH4)2CO3 in the presence of NH4Cl and NH4OH
- Precipitate: White ppt. of carbonates
- Confirmation Tests:
- Ba2+: Dissolve ppt. in HCl, add K2CrO4 → Yellow ppt. of BaCrO4
- Ca2+: Dissolve ppt. in HCl, add (NH4)2C2O4 → White ppt. of CaC2O4
- Sr2+: Flame test → Crimson red flame
Group VI: Mg2+, K+, NH4+
- Mg2+:
- Reagent: NH4OH + Na2HPO4
- Precipitate: White crystalline ppt. of MgNH4PO4
- K+:
- Flame test → Violet flame (observe through blue glass to filter out Na+ interference)
- NH4+:
- Warm the original solution with NaOH → Release of NH3 gas, detected by red litmus paper turning blue
Confirmative tests for acid radicals in Inorganic salt mixture Vido Url:
https://youtu.be/m_NZM5_Kyic?si=vk7AiFekDcOg8Rhy
https://youtu.be/0hjSVtBMLh4?si=2UHQ2U4xvz8-NiUq
1st Group Separation Analysis
https://youtu.be/AI6ap6mkaMQ?si=DJ09_OWX-l40CBLO
https://youtu.be/qpc9Lenn1_w?si=mAvf3-tgsi8JkGyi
5th group separation table
3rd Group Separation Analysis
https://youtu.be/Th_BMKams2w?si=J_zCM0os42PGBkmS
4th Group Separation Analysis
https://youtu.be/Md17KddV_g0?si=hTN6HLFLPUP0PLhH
5th Group Separation Analysis
https://youtu.be/gPSw0Y4_YZk?si=rFz3oABbOZkDzwHm
6th Group Separation Analysis
https://youtu.be/PLwT08Fhy3o?si=UY78mb6ZnZrtvtZk
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