e?

!Answer!: 84.47%.

52. A solution contains 50 grams of
KHC_{2}O_{4}.H_{2}C_{2}O_{4}.2H_{2}O per liter. What is the normal
value of the solution (a) as an acid, and (b) as a reducing agent?

!Answers!: (a) 0.5903 N; (b) 0.7872 N.

53. In the analysis of an iron ore containing 60% Fe_{2}O_{3}, a
sample weighing 0.5000 gram is taken and the iron is reduced with
sulphurous acid. On account of failure to boil out all the excess
SO_{2}, 38.60 cubic centimeters of 0.1 N KMnO_{4} were required to
titrate the solution. What was the error, percentage error, and what
weight of sulphur dioxide was in the solution?

!Answers!: (a) 1.60%; (b) 2.67%; (c) 0.00322 gram.

54. From the following data, calculate the ratio of the nitric acid as
an oxidizing agent to the tetroxalate solution as a reducing agent:
1 cc. HNO_{3} = 1.246 cc. NaOH solution; 1 cc. NaOH = 1.743 cc.
KHC_{2}O_{4}.H_{2}C_{2}O_{4}.2H_{2}O solution; Normal value NaOH =
0.12.

!Answer!: 4.885.

55. Given the following data: 25 cc. of a hydrochloric acid, when
standardized gravimetrically as silver chloride, yields a precipitate
weighing 0.5465 gram. 24.35 cc. of the hydrochloric acid are exactly
equivalent to 30.17 cc. of KHC_{2}O_{4}.H_{2}C_{2}O_{4}.2H_{2}O
solution. How much water must be added to a liter of the oxalate
solution to make it exactly 0.025 N as a reducing agent?

!Answer!: 5564 cc.

56. Ten grams of a mixture of pure potassium tetroxalate
(KHC_{2}O_{4}.H_{2}C_{2}O_{4}.2H_{2}O) and pure oxalic acid
(H_{2}C_{2}O_{4}.2H_{2}O) are dissolved in water and diluted to
exactly 1000 cc. The normal value of the oxalate solution when used as
an acid is 0.1315. Calculate the ratio of tetroxalate to oxalate used
in making up the solution and the normal value of the solution as a
reducing agent.

!Answers!: 2:1; 0.1577 N.

57. A student standardized a solution of NaOH and one of KMnO_{4}
against pure KHC_{2}O_{4}.H_{2}C_{2}O_{4}.2H_{2}O and found the former
to be 0.07500 N as an alkali and the latter exactly 0.1 N as an
oxidizing agent. By coincidence, exactly 47.26 cc. were used in each
standardization. Find the ratio of the oxalate used in the
NaOH standardization to the oxalate used in the permanganate
standardization.

!Answer!: 1:1.

58. A sample of apatite weighing 0.60 gram is analyzed for its
phosphoric anhydride content. If the phosphate is precipitated as
(NH_{4})_{3}PO_{4}.12MoO_{3}, and the precipitate (after solution and
reduction