71. Consider the following conditions regarding ideal washing liquid:

1. It should have no dispersive action on the precipitate
2. It should form volatile or insoluble product with the precipitate
3. It should be easily volatile at the drying temperature of the precipitate
4. It should have solvent action on the precipitate

Which of the above conditions are complying ideal washing liquid?
(a) 1 and 4 only
(b) 1 and 3 only
(c) 2 and 4 only
(d) 2 and 3 only

Answer: (b)

72. Consider the following procedure in chemical analysis:
1. Reduction of particle size
2. Mixing for homogeneity
3. Drying
4. Determination of sample weight or volume

During which one of the following stages the above procedure will be used in chemical analysis?
(a) Sampling
(b) Preparation of analytical sample
(c) Dissolution of sample
(d) Removal of interferences

Answer: (b)

73. Consider the following criteria regarding analytical method:
1. The type of analysis required: elemental or molecular, routine or occasional
2. Problems arising from the nature of the material to be investigated
3. Possible interference from components of the material other than those of interest
4. No need to investigate concentration range

Which of the above criteria require careful consideration to the choice of analytical method?
(a) 1, 2 and 4 only
(b) 1, 2 and 3 only
(c) 1, 3 and 4 only
(d) 2, 3 and 4 only

Answer: (b)

74. When metal ions are converted in to chelate compounds by treatment with suitable organic reagents; the resulting complexes are soluble in organic solvents and can be extracted from the aqueous solution. This method is known as:
(a) Selective precipitation
(b) Selective oxidation
(c) Solvent extraction
(d) Ion exchange

Answer: (c)

75. A substance that alters the rate of a reaction without itself undergoing any net change is:
(a) Metal
(b) Catalyst
(c) Non-metal
(d) Polymer

Answer: (b)

76. Sodium ethanoate is derived from:
(a) Strong acids and strong base
(b) Weak acids and strong base
(c) Strong acids and weak base
(d) Weak acids and weak base

Answer: (b)

77. The equilibrium in a dilute solution of salt, mass action (MA) may be represented as:

Answer: (b)

78. 

Answer: (c)

79. Consider the following statements for reducing the systematic errors in chemical quantitative analysis:
1. Calibration of apparatus and application of corrections
2. Running of blank determination
3. Running a control determination
4. Running parallel determinations

Which of the above statements are correct?
(a) 1, 2 and 3 only
(b) 1, 2 and 4 only
(c) 1, 3 and 4 only
(d) 1, 2, 3 and 4

Answer: (d)

80. Aqua regia is:

Answer: (a)