--%>
Assignment Help - homework help

Help

1) Chromium(III) hydroxide is highly insoluble in distilled water but dissolves readily in either acidic or basic solution. Briefly explain why the compound can dissolve in acidic or in basic but not in neutral solution. Write appropriate equations to support your answer. 2) Explain how dissolving the Group IV carbonate precipitate with 6M CH3COOH, followed by the addition of extra acetic acid, establishes a buffer with a pH of approximately 5. 3) A solution contains either Cr3+ or Ni2+ ion. Describe the reaction with a single reagent that will identify which ion is present. 4) The addition of S2- ion to Fe(OH)2(s). Explain why the addition of S2- ion to Cr(OH)3(s) does not result in the formation of Cr2S3(s). 5) A black precipitate remaining from the separation of Cr3+ and Fe2+ ions from Ni2+ ion is dissolved in HCl HNO3. Some NH3 is added, followed by several drops of dimethylglyoxime. a) A colorless solution results. What do you think has happened? b) What might have gone wrong? 6) A student was analyzing an unknown containing only Group IV cations. When the unknown was treated with 3M (NH4)2CO3 solution, a white precipitate formed. Because the acetic acid bottle was empty, the student used 6M HCl to dissolve the precipitate. Following the procedure of this experiment, the student then added 0.10M K2CrO4 solution as directed and no precipitate formed. Oxalic acid was added to the solution, and no precipitate formed. a) What mistake did the student make? b) How did the mistake affect the tests for the cations in solution?

   Related Questions in Chemistry

  • Q : Explain oxygen and its preparation.

    Karl Scheele, the Swedish chemist, was

    		•
  • Q : What are heterogenous catalysis? Give

    When the catalyst exists in a different phase than that of reactants, it is said to be heterogeneous catalyst, and the catalysis is called heterogeneous catalysis. For example, SO2 can be oxidized to SO3

    		•
  • Q : Molecular Properties Symmetry Molecular

    Molecular orbitals and molecular motions belong to certain symmetry species of the point group of the molecule.Examples of the special ways in which vectors or functions can be affected by symmetry operations are illustrated here. All wave functions soluti

    		•
  • Q : Question associated to vapour pressure

    Choose the right answer from following. The vapour pressure lowering caused by the addition of 100 g of sucrose(molecular mass = 342) to 1000 g of water if the vapour pressure of pure water at 25degree C is 23.8 mm Hg: (a)1.25 mm Hg (b) 0.125 mm Hg (c) 1.15 mm H

    		•
  • Q : Normality of acetic acid Give me answer

    Give me answer of this question. The normality of 10% (weight/volume) acetic acid is: (a)1 N (b)10 N (c)1.7 N (d) 0.83 N

    		•
  • Q : F-centres If a electron is present in

    If a electron is present in place of anion in a crystal lattice, then it is termed as: (a) Frenkel defect  (b) Schottky defect  (c) Interstitial defects (d) F-centre Answer: (d) When electrons are trapped in anion vacancies, thes

    		•
  • Q : Q what is the basicity of primary

    what is the basicity of primary secondary and tertiary amines in chlorobenzene

    		•
  • Q : Precipitation Addition of conc. HCl to

    Addition of conc. HCl to saturated Bacl2 solution precipitates Bacl2 ; because of the following reason : (a) It follows from Le Chatelier's principle (b) Of common-ion effect (c) Ionic product (Ba++)(cl) remains constant in a saturated sol

    		•
  • Q : What are isotonic and hypotonic

    The two solutions which are having equivalent osmotic pressure are called isotonic solutions. The isotonic solutions at the same temperature also have same molar concentration. If we have solutions having different osmotic pressures then the solution having different

    		•
  • Q : Kinds of insulators Describe all the

    Describe all the kinds of insulators which are present?

    		•