1.Copper is an interference of iron determination using the thiocyanate method. Explain the mechanism of interference and suggest a method to overcome the interference.

2.The standard and sample solutions are prepared in 2 M HCl to acidify the sample. Explain if H2SO4can be used instead of HCl .

3.Suggest an alternative complexing agent for spectrophotometric determination of iron

Which is true of transition metals when moving from left to right on the periodic table? the d sublevels are not filled across the period. the cation radii become larger across the period. atomic radii increase slightly and then start to decrease. atomic radii decrease slightly and then start to increase. o

The semi-conductors on the periodic table are classified as

A0.10 m aqueous solution of sodium sulfate is a better conductor of electricity than a 0.10 m aqueous solution of sodium chloride. which of the following best explains this observation? (a) sodium sulfate is more soluble in water than sodium chloride. (b) sodium sulfate has a higher molar mass than sodium chloride. (c) to prepare a given volume of 0.10 m solution, the mass of sodium sulfate needed is more than twice the mass of sodium chloride needed. (d) more moles of ions are present in a given volume of 0.10 m sodium sulfate than in the same volume of 0.10 m sodium chloride. (e) the degree of dissociation of sodium sulfate in solution is significantly greater than that of sodium chloride.