Salt Analysis and Qualitative Analysis Exercise # 3

SALT ANALYSIS AND QUALITATIVE ANALYSIS Exercise # 3 1. Part # I Match the precipitates listed in column-I with their suitable solvents listed in column-II. Column I (precipitate) (A) AgCl (white) (B) CuS (black) (C) Zn(OH)2 (white) (D) Ba(CO3) (white) 2. Column-II (p) H2S (saturated solution in water) (q) Potassium thiocyanate solution (r) Potassium iodide solution (s) Potassium ferrocyanide solution (t) Sodium hydroxide solution. Match the basic radicals listed in column-I with the properties listed in column-II. Column-I (Basic radical) (A) Mn2+ Column-II (Properties) (p) Forms coloured metaborate in oxidising flame in borax bead test. (q) Forms white precipitate with sodium hydroxide but on exposure to air turns rapidly brown. (r) With both potassium cyanide (not in excess) and ammonia solution separately forms reddish brown precipitate. (s) With excess of sodium hydroxide forms soluble complex but on adding acid to soluble complex, a precipitate is obtained which redissolves on adding excess of acid. (B) Cr3+ (C) Al3+ (D) Fe3+ 4. Column II (solvent) (p) Concentrated HCl. (q) Dilute ammonia solution (excess). (r) Potassium cyanide solution. (s) Hot 50% nitric acid. Match the colour of the precipitates listed in column-I with the suitable reagent(s) in column-II. Column-I (A) Bi3+ give(s) black precipitate with (B) Cu2+ give(s) black precipitate with (C) Zn2+ give(s) white precipitate with (D) Ag+ give(s) white precipitate with 3. [Matrix Match Type Questions] Match the following Column–I (A) Fe(SCN)3 + KF (aq) excess (B) CrO2Cl2 + NaOH (aq) Column–II (p) Produce coloured product (s) (q) diamegnatic product 3  (C) Ni+2 + dmg  CH 3 COONa (r) Hydrogen bonded product H (D) Na2SO3 + Cr2O 72   (s) Tetrahedral geometry around metal CH COOH Note :- dmg = dimethyl glyoxime 5. Match the following Column–I (A) CrCl3 (aq) (B) CuSO4 (aq) (C) (NH4)2 CO3 (aq) (D) AgNO3 (aq) Column–II (p) Produce ppt with excess of NaOH (q) Produce coloured Solution with excess of amonia (r) Produce gases product when heated with KOH (aq) (s) Produce gas with dil. H2SO4 6. 7. 8. Match the following Column–I Column–II (A) Colourless gas evolved on addition (p) S2O 23  of dil. H2SO4 (B) White ppt. on addition of AgNO3 (q) S2– (C) Black ppt. obtained when HgCl2 (r) NO 2 is added in little amount (D) The ppt. obtained on addition of AgNO3 followed by NH3 solution (s) CH3CO2– Match the following Column–I (A) Soluble in a concentrated NH3 solution (B) Soluble in excess KCN solution (C) Soluble in excess hypo solution (D) Soluble in conc. HCl Match the following Column–I (A) H3P3O9 (B) H2S2O7 (C) H2S4O6 (D) H4P2O5 Part # II Column–II (p) Ag2S (q) Cu(OH)2 (r) AgBr (s) AgCl Column–II (p) S–O–S bond is present (q) Di-basic acid (r) P–O–P bond is present (s) Central atom (S or P) in maximum oxidation state [Comprehension Type Questions] Comprehension # 1 A student was given a sample of colourless solution containing three cations and was asked to identify the cations. Student carried out a series of reactions as given below. SALT ANALYSIS AND QUALITATIVE ANALYSIS 1. 2. 3. Precipitates ‘A’, ‘B’ and ‘C’ are respectively : (A) Al(OH)3, BaSO4 and AgCl (C) AgCl, Ca(OH)2 and ZnSO4 (B) AgCl, BaSO4 and Zn(OH)2 (D) ZnCl2, BaSO4 and Al(OH)3 White precipitate 'A' is not soluble in : (A) NH3 (B) 2M HCl (C) KCN (D) Na2S2O3 Which of the following statement is correct ? (A) Precipitate 'C' gives Rinmann's green test. (B) Precipitate 'B' is appreciably soluble in boiling concentrated H2SO4. (C) Precipitate (A) on exposure to sunlight or ultraviolet radiations turns black. (D) All of these. Comprehension # 2 H S ( g) Aqueous solution of ‘A’ 2  Black precipitate ‘B’, soluble in 50% HNO3 forming ‘C’. White precipitate dissolves in hydrochloric acid but on dilution with water again white turbidity appears 'E'. Black precipitate ‘D’ Moreover, the salt 'A' on heating with solid K2Cr2O7 and concentrated H2SO4 produces deep red vapours which dissolve in sodium hydroxide solution forming a yellow solution. This yellow solution gives yellow precipitate with Ba(NO3)2 solution. On the basis of the aforesaid characteristic informations answer the following questions : 1. Acidified solution of ‘A’, on treatment with KI gives black precipitate 'F' which dissolves in excess of reagent forming the coloured compound 'G'. The chemical composition of 'F' and 'G' are respectively : (A) HgI2 and [HgI4]2– (B) PbI2 and [PbI4]2– (C) BiI3 and [BiI4]– (D) Cu2I2 and CuI2. 2. The black precipitate 'F' on heating with water produces : (A) Hg(OH)2 (B) BiOI (C) BiO.OH (D) CuO.OH 3. Which of the following statements is incorrect? (A ) The black precipitate 'D' is of bismuth. (B) The black precipitate 'D' is of Hg + Hg(NH2)NO3. (C) Aqueous solution of 'A' gives yellow precipitate with freshly prepared 10% solution of pyrogallol. (D) Aqueous solution of 'A' gives red precipitate with 8-hydroxyquinoline (5%) and potassium iodide (6M) in acidic medium. 4. Select the correct statement. (A) Aqueous solution of 'A' reacts with AgNO3 solution to give white precipitate which turns yellow on treatment with sodium arsenite. (B) Aqueous solution of 'A' produces white precipitate with sodium hydroxide which turns yellowish-white on boiling. (C) White turbidity 'E' is soluble in dilute mineral acids. (D) All of these. Reaction involved in comprehension :  H Bi S  (black) (B) + 6 H+ 2Bi3+ (A) + 3H2S  2 3 Bi2 S3 + 8HNO3  2Bi (NO3)3 (C) + 2NO + 3S + 4H2O NaOH 2Bi(OH)3  (white) + 3[Sn(OH)4]2–  2Bi (D) + 3[Sn(OH)6]2– Bi3+ + 3OH–  Bi(OH)3 (white) ; NH4OH   Bi(OH)3 (white) ; Bi(OH)3 (white) + 3HCl  BiCl3 + 3H2O Bi3+ + 3OH–  BiCl3 + H2O  BiOCl  (bismuth oxychloride) (E) + 2HCl 4NaCl + K2Cr2O7 + 3H2SO4 (conc.)  2CrO2Cl2 (deep red vapours) + 2Na2SO4 + K2SO4 + 3H2O CrO2Cl2 + 4OH–  CrO42– + 2Cl– + 2H2O CrO42– + Ba2+  BaCrO4 (yellow). Comprehension # 3 Read the following comprehension carefully and answer the following questions. [A] coloured salt K2Cr2O7+H2SO4 (conc.) Heat NH4OH + NH4Cl (B) Deep reddish orange vapour NaOH (aq.) Water (C) Yellow solution 1. (F) Fusion with Na2CO3+KNO3 & extraction with water 1st part + AgNO3(aq) 2nd part + BaCl2 (aq) (D) (E) The colour of the ppt (D) & (E) are : (A) white & yellow (B) yellow (G) Green ppt (C) brick red & yellow (D) yellow and brick red 2. Yellow solution (C) is an important laboratory reagent and is used in the estimation of : (A) Pb2+ (B) Fe3+ (C) Cd2+ (D) None of these 3. The compound (A) is : (A) CrCl3 (B) CrBr3 4. (C) Cr(CH3COO)3 [A] (s) + MnO2 + H2SO4 (conc.)  X Greenish yellow gas. Select the correct choice for [X] : (A) It gives yellow ppt. with AgNO3 (B) It liberates I2 from KI solution (C) It turns starch paper orange red (D) It turns titan yellow solution red (D) Cr(NO3)3 SALT ANALYSIS AND QUALITATIVE ANALYSIS Comprehension # 4 A chemist opened a cupboard to find four bottles containing water solutions, each of which has lost its label. Bottles 1, 2, 3 contained colourless solutions, whilst Bottle 4 contained a blue solution. The labels from the bottles were lying scattered on the floor of the cupboard. They were Copper (II) sulphate Sodium carbonate Lead nitrate hydrochloric acid By mixing samples of the contents of the bottles, in pairs, the chemist made the following observations : 1. 2. 3. 4. (i) Bottle 1 + Bottle 2 white precipitate (ii) Bottle 1 + Bottle 3 white precipitate (iii) Bottle 1 + Bottle 4 white precipitate (iv) Bottle 2 + Bottle 3 colourless gas evolved (v) Bottle 2 + Bottle 4 no visible reaction (vi) Bottle 3 + Bottle 4 blue precipitate Chemical formula of white precipitate in observation (i) is : (A) CuCl2 (B) PbCl2 (C) PbCO3 (D) CuSO3 Colourless solution present in Bottle-1 is (A) CuSO4 (B) HCl (C) Pb(NO3)2 (D) Na2CO3 Nature of gas evolved in observation (iv) is (A) Acidic (B) Neutral (C) Basic (D) Amphoteric Chemical formula of white ppt. formed in observation (iii) is : (A) PbCl2 (B) PbCO3 (C) CuCO3 (D) PbSO4 Comprehension # 5 Read the following short write up and answer subsequent questions based on observations (A) to (J). white ppt. soluble in aq NH3 AgNO3 coloured ppt. soluble in excess NaOH NaOH green coloured solution of a compound (A) KOH/H2O 2 yellow coloured solution (B) H2SO4 1. 2. 3. Compound A and B are respectively : (A) FeCl2 ; FeCl3 (C) CrCl3 ; K2CrO4 (B) CuCl2 ; 2H2O ; [CuCl4]–2 (D) NiCl2 ; NiCl3 Gas (J) is also produced by : (i) heating NH4NO3 (iii) heating NH4Cl (A) (i) and (iii) (B) (i) and (ii) (ii) heating NH4NO2 (iv) Reaction of NH4Cl and Ca(OH)2 (C) (i) and (iv) (D) (iii) and (iv) Select the incorrect reaction : (A) (C) in solid state + KBr + conc. H2SO4 (B) (C) in solid state + KCl + conc. H2SO4 (C) (C) in solid state + FeCl3 + conc. H2SO4 (D) (C) in solid state + HgCl2 + conc. H2SO4     Red Red Red Red gas gas gas gas SALT ANALYSIS AND QUALITATIVE ANALYSIS Comprehension # 6 Three metal ions x+2, y+2, z+2 are identify in qualitative analysis. Nitrates of x+2, y+2, z+2 dissolve in three seprate test tubes and gives following observation. 1. (i) All solution produce carbonate precipitate with (NH4)2CO3 (ii) Only one produce white ppt on addition of NaCl. (iii) Out of 3 cations two produce sulphide ppt. (iv) (v) Sulphide of y+2 is not produce by H2S/H+ but produce when H2S is passed in basic medium. Only y+2 produce soluble sulphate (vi) x+2 gives no ppt with dil NH4OH. Select in correct statement : (A) y+2 not produce precipitate with Ist group reagent in salt analysis (B) y+2 not produce ppt with 2nd group reagent in salt analysis (C) z+2 produce ppt with IInd group reagent in salt analysis (D) z+2 is not produce ppt with Ist group reagent in salt analysis 2. 3. 4. Select order of Ksp of sulphide of x+2, y+2, z+2 (A) xs > ys > zs (B) xs > zs > ys (C) ys > zs > xs (D) zs > ys > xs Select correct about xCO3, y CO3, z CO3 (A) All are soluble in dil. H2SO4 (B) All are soluble in dil HCl (C) None is soluble in dil. H2SO4 (D) Except ZCO3 all are soluble in dil. HCl NH 4 OH  (i) x+2 + H2S  (ii) x+2 + NaOH (dil)  (iii) x+2 + Na2CO3  Precipitate is obtain in (A) Reaction (i), (ii), (iii) (B) Only in reaction (iii) (C) Only in reaction (i) and (ii) (D) Only in reaction (ii) EXERCISE - 3 : PART # I PART # II 1. A p, q, r, B r, s, C p, q, s, t, D p, s 2. A p, r, B p, q, C p, s, D q, s Comprehension # 1 : 1. B 2. B 3. D 3. A p, q, B p, s, C s, D p, r Comprehension # 2 : 1. C 2. B 3. B 4. D 4. A q, B p, q, s, C p, q, r, D p, q, s Comprehension # 3 : 1. C 2. A 3. A 4. B 5. A q, B p, q, C r, s, D p Comprehension # 4 : 1. B 2. C 3. A 4. D 6. A p, q, s, B p, r, s, C q, D q Comprehension # 5 : 1. C 2. D 3. D 7. A p, r, B p, q, C p, r, D p, q, s Comprehension # 6 : 1. D 2. A 3. D 4. B 8. A q, r, s, B p, q, r, s, C q, r, s, D q, s