Suggest,What are the best topics to make on chart for class 12 chemistry practicals exam?
Answers
Answer:
The first washing machine was called as the scrub board and was invented in the year 1797. In 1851, American James King discovered and patented the first washing machine to use a drum. However it was still hand powered and did not work by itself
Explanation:
Surface chemistry
(a). Preparation of one lyophilic and one lyophobic sol
Lyophilic sol - starch, gum and egg albumin
Lyophobic sol- aluminium hydroxide, ferric hydroxide, arsenous sulphide.
(b). Dialysis of sol-prepared in (a) above.
(c). Study of the role of emulsifying agents in stabilizing the emulsion of different oils.
B - Chemical Kinetics
(a). Effect of concentration and temperature on the rate of reaction between Sodium Thiosulphate & Hydrochloric acid.
(b). Study of reaction rates of any one of the following:
(i). Reaction of Iodide ion with Hydrogen Peroxide at room temperature using different concentration of Iodide ions.
(ii). Reaction between Potassium lodate, (KIO3,) & Sodium Sulphite: (Na2SO3,) using starch solution as indicator (clock reaction).
C - Thermochemistry
Any one of the following experiments
(i). Enthalpy of dissolution of Copper Sulphate or Potassium Nitrate.
(ii). Enthalpy of neutralization of strong acid (HCl) and strong base (NaOH).
(iii). Determination of enthalpy change during interaction (Hydrogen bond formation) between Acetone and Chloroform.
Electrochemistry
Variation of cell potential in Zn/Zn2+ || Cu2+/Cu with change in concentration of electrolytes (CuSO4 or ZnSO4) at room temperature.
E - Chromatography
(i). Separation of pigments from extracts of leaves and flowers by paper chromatography and determination of Rf values.
(ii). Separation of constituents present in an inorganic mixture containing two cations only (constituents having large difference in Rf values to be provided).