Independent group: sulphate, phosphate, borate

38 questions on Independent group: sulphate, phosphate, borate from the Qualitative Analysis: Anions chapter: 8 NEET level, 15 JEE Main, 15 JEE Advanced. Each one opens with its answer and solution.

• A white precipitate is obtained when barium chloride solution is added to an aqueous salt solution, and the precipitate does not dissolve on adding dilute hydro... NEET level
• Warming a salt solution with ammonium molybdate in the presence of concentrated nitric acid gives a canary-yellow precipitate. The anion tested is NEET level
• A borate salt is heated with ethanol and a few drops of concentrated sulphuric acid and the vapour is ignited. The flame is bordered by which colour? NEET level
• A salt imparts a brick-red colour to a non-luminous Bunsen flame. The cation present is NEET level
• Magnesia mixture (MgCl2 + NH4Cl + aqueous NH3) is added to a solution of sodium hydrogen phosphate. The white crystalline precipitate formed is JEE Main level
• Assertion (A): White BaCO3 dissolves in dilute HCl, but white BaSO4 does not. Reason (R): CO3^2- is the conjugate base of a weak, unstable acid H2CO3 and is rem... JEE Main level
• Which statement about the turmeric paper test for borate is correct? JEE Main level
• A white precipitate X is insoluble in dilute nitric acid but dissolves in hot concentrated ammonium acetate solution. The resulting solution gives a yellow prec... JEE Main level
• Which of the following statements about borate analysis are correct? One or more options may be correct. JEE Main level
• A solution gives a white precipitate with BaCl2. On adding dilute HCl the precipitate dissolves only partly, a colourless gas with a suffocating smell is evolve... JEE Main level
• In the yellow precipitate (NH4)3[P(Mo3O10)4], the oxidation states of P and Mo respectively are JEE Main level
• A 0.500 g sample of pure anhydrous Na2SO4 is dissolved in water, acidified with dilute HCl and treated with excess BaCl2 solution. Taking Na 23, S 32, O 16 and ... JEE Main level
• A white crystalline salt X dissolves in hot water to give an alkaline solution, swells and fuses to a glassy mass on strong heating, gives a green-edged flame w... JEE Advanced level
• A colourless salt Y dissolves in water. It gives no precipitate with BaCl2 in the presence of dilute HCl, evolves a gas that turns moist red litmus blue on warm... JEE Advanced level
• A sodium salt solution (neutral) gives a yellow precipitate with AgNO3 that dissolves in both dilute HNO3 and aqueous NH3. Which of the following observations w... JEE Advanced level
• Barium sulphate obtained from a sulphate is heated strongly with carbon: BaSO4 + 4C -> BaS + 4CO. The product is dissolved in dilute HCl and the gas evolved is ... JEE Advanced level
• A borax bead containing a trace of a metal salt is heated in the oxidising flame and then cooled. It is violet, but becomes colourless in the reducing flame. Th... JEE Advanced level
• Ammonium molybdate reacts with phosphate in strongly acidic (nitric acid) solution according to PO4^3- + 12MoO4^2- + 3NH4+ + 24H+ -> (NH4)3[P(Mo3O10)4] + 12H2O.... JEE Advanced level
• In a laboratory preparation of triethyl borate for the green-flame test, 0.25 mol of borax (Na2B4O7) is treated with dilute sulphuric acid to liberate boric aci... JEE Advanced level
• A salt solution gives a white precipitate with BaCl2 solution that does not dissolve in dilute HCl. The anion present is NEET level
• A phosphate solution is warmed with ammonium molybdate in the presence of conc. HNO3. The precipitate formed is NEET level
• Boric acid is heated with ethanol and a few drops of conc. H2SO4 and the vapour is ignited. The flame is NEET level
• A borax bead is prepared and heated in the oxidising flame after touching it to a copper(II) salt. The colour of the cold bead is NEET level
• Phosphate solution is treated with magnesia mixture (MgCl2, NH4Cl and aqueous NH3). The white crystalline double salt formed is JEE Main level
• Silver nitrate is added to a neutral solution of a sodium salt and a yellow precipitate forms, which dissolves in both dilute HNO3 and aqueous NH3. The precipit... JEE Main level
• In the test for sulphate, the solution is acidified with dilute HCl before adding BaCl2. The main reason is JEE Main level
• BaCl2 solution is added dropwise to a solution that is 2.0x10^-3 M in SO4^2-. Take K_sp(BaSO4) = 1.1x10^-10 and neglect dilution. The minimum [Ba^2+] at which B... JEE Main level
• Match the anion in List I with its confirmatory observation in List II. List I: (i) sulphate; (ii) phosphate; (iii) borate. List II: (p) canary yellow precipita... JEE Main level
• Boric acid, B(OH)3, behaves as a weak monobasic acid by accepting OH- to form [B(OH)4]-. The hybridisation of boron changes from JEE Main level
• A borax bead, after touching a salt and heating in the oxidising flame, is violet (amethyst) when cold. The salt contains JEE Main level
• A white solid X dissolves in water. With ammonium molybdate in warm conc. HNO3 it gives a canary yellow precipitate (NH4)3[PMo12O40], and the anion in the preci... JEE Advanced level
• A borax sample is investigated. Which statements are correct? JEE Advanced level
• Which statements regarding the independent group anions are correct? JEE Advanced level
• Which of the following are correct for boron compounds met in the borate test? JEE Advanced level
• Each of the following solutions is treated with excess dilute HCl and then BaCl2 solution. Which give a white precipitate that persists? (Solutions 2 and 3 were... JEE Advanced level
• Assertion (A): The green flame test for borate is performed with ethanol (or methanol) and conc. H2SO4, not with dilute acid. Reason (R): Formation of the volat... JEE Advanced level
• A solution contains 0.0100 mol Na2SO4 and 0.0100 mol Na3PO4. Excess BaCl2 is added at neutral pH, forming both barium salts completely, and then excess dilute H... JEE Advanced level
• A solution of Na2HPO4 in excess is treated with 0.030 mol of AgNO3, forming yellow Ag3PO4 completely according to 3Ag+ + HPO4^2- -> Ag3PO4 + H+. The amount of H... JEE Advanced level