White precipitate shows the presence of chloride (Cl-). Chloride anion equation: HCl(aq) + AgNO3 (aq) → HNO3 (aq) + AgCl(s). The nitrate anion test involves cooling a mixture containing 1 mL of test solution and 3mL 18M H2SO4. 2mL is poured down the inner test tube side and the presence of a brown ring shows nitrate (NO3-) to be present. The carbonate anion test mixes 1 mL of test solution and drops of 6M HCl.
When the solution is acidified during diazotization to form nitrous acid, the sulfanilic acid is precipitated out of solution as a finely divided solid, which is immediately diazotized. The finely divided diazonium salt is allowed to react immediately with dimethlaniline in the solution in which it was precipitated. Mechanism Diazotization: [pic] Diazo Coupling: Methyl orange is often used as an acid-base indicator. In solutions that are more basic than pH 4.4, methyl orange exists almost entirely as the yellow negative ion. In solutions that are more acidic than pH 3.2, it is protonated to form a red dipolar ion.
Silver nitrate tested for 2o and 3o alkyl halides expected in dibromocholesterol and sulfuric acid tested for alkenes expected in cholesterol. Bromination had 68.8% yield, debromination 73.7% yield, and overall 53.3% of commercial cholesterol was recovered as synthesized cholesterol. For commercial cholesterol, dibromocholesterol, and synthesized cholesterol, melting points were 145.2-148.1oC, 109.0-110.1oC, 146.3-148.2oC and retention factor (Rf) values were 0.69, 0.80 respectively. Chemical tests confirmed expectations, though some alkenes were present in dibromocholesterol. The similar melting points of the synthesized product as compared to the literature value; and similar Rf values for commercial and synthesized cholesterol showed the purity of
Title : Reaction of Carboxylic Acids Objective : To Determine The Reaction of Carboxylic Acids Procedure : As referred to Lab manual. Results: A. Salt Formation |Compound |Solvent |Solubility | |Benzoic Acid |Cold Water |Partially soluble | |Benzoic Acid |10 % NaOH |Soluble | B. Salt Hydrolysis Sodium acetate solution changed the color of litmus from red to blue. C. Reaction With Sodium Carbonate Observation : A lot of gas bubbles was released.
5.51: Which Reagent is limiting and How Much Precipitate is formed? SCH-3UI-03 David Yu Mrs. Hatton Due Date: May 5, 2012 Cut-Off Date: May 12, 2012 Purpose: To experience and use what you have learned in class about gravimetric stoichiometry by predicting and determining the mass of precipitate of two reactants and then comparing what you experience and what you calculated. Background: Avogadro’s constant is 6.02 x 1023 to find the number of entities. A mole is a useable amount of chemicals that is practical to use. The molar mass of a compound or atom is the mass of 1 mole of anything; this is relative to the atomic mass from the periodic table.
UNIVERSITI TUNKU ABDUL RAHMAN Faculty Course Year/ Semester Session : : : : Faculty of Science Bac. of Science (Hons) Chemistry Year 3 Semester 1 201105 or May 2011 Unit Code Unit Title Lecturer Assignment : : : : UDEC3254 Spectroscopy and Chromatography II Dr. Lim Chan Kiang 2 Answer all questions 1. A mixture of steroid hormones consisting of cortisone, cortexone and corticosterone was separated using a HPLC silica column eluted with a binary mixture of acetone and hexane (20:80). (i) What is the order of elution time for the above compounds from the HPLC column? (3 marks) (ii) What is the chromatographic mechanism involved?
Three drops of phenolphthalein indicator was added into the HCl solution. The stopcock was opened and the NaOH solution was added into the HCl solution. The flask was swirled to mix the solutions and titrate to a faint pink end point. Recorded the final volume on the butret and used the final volume as a beginning volume to repeat the titration. At the second titration, the experiment was exactly the same as the first titration but the H2SO4 solution was used to instead of the HCl solution.
LIQUID-LIQUID EXTRACTION OF BENZOIC ACID J Wright Organic Chem Lab 1 Tuesday 1:40-5 Ian Stubbs LIQUID-LIQUID EXTRACTION OF BENZOIC ACID PURPOSE: The purpose of this experiment was to extract benzoic acid from an aqueous of benzoic acid using methylene chloride, use liquid-liquid extraction to calculate the distribution coefficient of benzoic acid and to determine whether a single extraction or multiple extractions are more efficient. Add in the table of physical constants. See the attachment for the lab format. PROCEDURE: Gather a two stock solution that includes; 0.02M of sodium hydroxide (NaOH) aqueous solution and 0.02M of benzoic acid aqueous solution. For a single extraction, use a 50mL graduated cylinder and measure out 50mL of the benzoic acid solution into a 125mL separatory funnel.
Background: For the entire explanation of this demo see Shakhashiri's Chemical Demonstrations, Vol. 4, pp 42-43. The following is a excerpt from this volume. " The sudden change from colorless to deep blue solutions in this demonstration can be explained with the following sequence of equations: 3 I-(aq) + H202 + 2 H+ (aq) = I3- (aq) + 2 H20 (l) (1) I3- (aq) + 2 S2O3 2- (aq) = 3 I- (aq) + S4O6 2- (aq) (2) 2 I3- (aq) + starch = starch-I5- complex + I- (aq) (3) The first equation indicates that, in an
Title Page Experiment Title: Experiment 4: Qualitative Analysis of Cations III – Mg2+, Ca2+, Fe3+, Ba2+. Aim To determine the presence of the cation II , Mn2+, Ni2+, Fe3+, (Fe2+), Al3+, Zn2+ by using separation method to confirm the presence of cation II in the test solution. Procedure Please refer to the laboratory manual page 30-31. Results Procedure Number and Ion | Test Reagent or Technique | Evidence of Chemical Change | Chemical(s) Responsible for Observation | Equation(s) for Observed Reaction | 1 | Centrifuge the solution. | A brown precipitate was formed.