Class 12 Lab Manual Chemistry

• Important 12 chemistry lab manual for Intermediate part-II students.
• To prepare a pure sample of aspirin
• Take 10g of salicylic acid in a round bottom flask. Add 10 cm³ of acetic acid and 10 cm³ of acetic anhydride in it. Boil this mixture under reflux for 30 minutes. Stop heating and add about 200 cm³ of ice cold water in it with vigorous stirring. White crystals of aspirin will be formed. Filter the crystals, dry them and show to the examiner.
• Important 12th chemistry lab manual for Intermediate part-II students.
• The melting point of acetyl salicyclic acid (aspirin) is 136-137°C.
• Take 10 cm³ of saturated solution of CuSO, in 100 cm³ beaker. Add ammonium hydroxide solution in it, drop wise. Firstly green colour appears, add more NH, till a dark blue colouration is obtained. Now add ethanol in it, till dark blue crystals of tetra ammine copper (II) sulphate [Cu(NH,),]SO, are formed. Filter the crystals, dry them and then show to the examiner.
• Important 12th lab manual chemistry for Intermediate part-II students.
• Dissolve 3g of Ghenyl hydrazi hydro-chloride in 10 cm³ of water containing 3 grams of sodium acetate in a clean round bottom flask. Warm gently on a water bath and shake the contents of flask until it dissolved. Male a solution of 1g of glucose in 3 5 cm water in a test tube separately. Add glucose solution into the round bottom flask and stir the contents of flask constantly. Place the flask in boiling water bath. After about 20 minutes, yellow crystals of phenyl glucasozone begins to separate. Cool down the contents of the flask and separate the yellow crystals of phenyl glucosazone by filteration.
• Important chemistry manual class 12 for Intermediate part-II students.
• Take 10 cm³ of the given solution of Bat ions in a 250 cm³ beaker. Dilute the solution to 50 cm³ with distilled water and then add NH OH till it smells ammonia. Then add 10% solution of K,CrO, till the supernatent layer stops giving any yellow ppt. on addition of KCrO, solution.
• Important class 12th chemistry lab manual for Intermediate part-II students.
• Stir the solution well and allowed to stand for 15 minutes. Filter the precipitate in a pre-weighed filter paper. Dry the precipitate in electric oven at 115 c° for 30 minutes and calculate the mass of BaCrO.
• Important chemistry lab record class 12 for Intermediate part-II students.
• Dissolve 20g of Na₂CO, in about 100 cm³ water is round bottom flask, heat the solution upto 60°C and add 20 cm³ of ethyl alcohol in it. Add powdered I, pinch by pinch in the mixture with constant shaking.
• Important class 12 chemistry practical manual for Intermediate part-II students.
• Continue the addition of I, with shaking until iodoform is separated out yellow crystals. Filtercand as dry the crystals of yellow coloured iodoforms and show to the examiner.
• Important laboratory manual chemistry class 12 for Intermediate part-II students.
• Take a small piece of Na metal in a fusion tube and heat upto melting of sodium. Add small amount of organic compound in fusion tube. Heat it till red-hot. Plunge fusion tube into china dish containing about 20 cm³ of distilled water.
• Important class 12 chemistry practical lab manual for Intermediate part-II students.
• Stir the solution and filter it. The filterate is called sodium fusion filterate or Lassaigne's filterate or sodium extract. Divide it into three parts.
• Important lab manual of class 12 chemistry for Intermediate part-II students.
• For preparing approximately IM NaOH, take 4 gm of it, and dissolve it in 100 cm³ of solution and for preparing approximately IM HCI, take 10 cm³ n of conc. HCI and dilute it to 100 cm³. With 3 distilled water. Prepare 0.5 M oxalic acid by dissolving 31.5 gms of it in 250 cm³. Of solution. First of all prepare standard solution of IM NaOH by it and then with standard IM HCI, prepare IM NaOH of exact molarity.
• Important lab manual of chemistry class 12 for Intermediate part-II students.
• "When hot super saturated solution is cooled at room temperature, solid crystals of benzoic acid are formed."Benzoic acid is slightly soluble in water at room temperature (0.5g/dm³). However appreciable amount is soluble at high temperature, so when the temperature is lowered crystals are formed.
• Important lab manual for class 12 chemistry for Intermediate part-II students.
• Now if a common ion e.g., Cl added in this solution by passing HCl gas, the molar concentration of CI ions increases and as a result Na' ions and Cl ions combined to form solid NaCl. Take NaCl in the round bottom flask and add conc. H₂SO₄ through thistle funnel in it. When H₂SO₄ reacts with NaCl solid, a colourless punget gas HCl will evolve which passes through the delivery tube into the beaker containing saturated solution of NaCl.
• Important class 12 chem lab manual for Intermediate part-II students.
• White crystals of pure NaCl will be precipitated out and settle down at the bottom. When no more crystals are formed, stop passing HCl gas. Separate the crystals of NaCl by filteration and dry them between folds of filter paper or in desiccator and show to the examiner.
• Important lab manual class 12th chemistry for Intermediate part-II students.
• Take 25cm³ of the solvent in chromatographic tank and cover the lid. Take a filter paper of appropriate size and mark a base line. Apply sample mixture in the middle of base line and dry the spot.
• Important chem class 12 lab manual for Intermediate part-II students.
• Place the filter paper in the tank with the help of hanger and leave it for half an hour. After 30 minutes remove the lid and put out chromatogram. Mark the solvent with lead pencil Dry the chromatogram and calculate R, values.