418 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS the difference between the addition of ammonia to (a) a solution of Zinc Chloride, and to (b) a solution of Zinc Chloride and Ammonium Chloride. 5. Define the term pH. Calculate the pH of (a) 0-002 N HC1, (b) 0.002 N NaOH. Describe the effect on (a) and (b) of the addition of respec- tively an equal volume of (i) 0.02 N CH•COONa, (ii) 0.02 N NH4C1 with respect to the hydrogen ion concentration before and after the additions (log•02 is 0.3010). 6. Describe the preparation of high-grade Carnauba Wax from natural sources and describe the Laboratory examination of the product. ß 7. Outline the gravimetric analysis of a sample of Talc. 8. Briefly describe th• Laboratory examination of a sample of Zinc Oxide with reference to Lead content and Arsenic content. EXAMINER'S REPORT Questions 1 and 2 were generally well answered, but in question 3 most candidates omitted too many points of detail in the analytical procedure. Question 4 was quite well answered most students showed that they had understood the qualitative application of the notion of Solubility Product. Question 5 was not well done some candidates were unable to calculate the hydrogen ion concentration of 0-002 N NaOH. Question 6 was generally well answered, nearly all answers including a satisfactory account of the extraction of the wax from the leaves. The question on gravimetric analysis of talc was not attempted by any candidate. Question 8, on the Laboratory examination of zinc oxide was well answered by some of the candidates, but otherwise the standard of answer was rather poor. It is commonly the case that in this examination the descriptive essay type of question is answered well. Most candidates are weak on Physical Chemistry and on Analytical procedure, and whenever possible they avoid questions requiring precise factual information. Their answers indicate a reluctance to concentrate on detail they have a desire to accept the study line of least resistance and to skate broadly over a subject. They must overcome this if they are to make good progress in the work on which they are engaged.

418 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS the difference between the addition of ammonia to (a) a solution of Zinc Chloride, and to (b) a solution of Zinc Chloride and Ammonium Chloride. 5. Define the term pH. Calculate the pH of (a) 0-002 N HC1, (b) 0.002 N NaOH. Describe the effect on (a) and (b) of the addition of respec- tively an equal volume of (i) 0.02 N CH•COONa, (ii) 0.02 N NH4C1 with respect to the hydrogen ion concentration before and after the additions (log•02 is 0.3010). 6. Describe the preparation of high-grade Carnauba Wax from natural sources and describe the Laboratory examination of the product. ß 7. Outline the gravimetric analysis of a sample of Talc. 8. Briefly describe th• Laboratory examination of a sample of Zinc Oxide with reference to Lead content and Arsenic content. EXAMINER'S REPORT Questions 1 and 2 were generally well answered, but in question 3 most candidates omitted too many points of detail in the analytical procedure. Question 4 was quite well answered most students showed that they had understood the qualitative application of the notion of Solubility Product. Question 5 was not well done some candidates were unable to calculate the hydrogen ion concentration of 0-002 N NaOH. Question 6 was generally well answered, nearly all answers including a satisfactory account of the extraction of the wax from the leaves. The question on gravimetric analysis of talc was not attempted by any candidate. Question 8, on the Laboratory examination of zinc oxide was well answered by some of the candidates, but otherwise the standard of answer was rather poor. It is commonly the case that in this examination the descriptive essay type of question is answered well. Most candidates are weak on Physical Chemistry and on Analytical procedure, and whenever possible they avoid questions requiring precise factual information. Their answers indicate a reluctance to concentrate on detail they have a desire to accept the study line of least resistance and to skate broadly over a subject. They must overcome this if they are to make good progress in the work on which they are engaged.