The answer would be D, all the above
Question 1
Fe(III) forms a chelate complex with salicylic acid which has purple color. therefore, when a solution is made either with salicylic acid or with aspirin having trae amount of salicylic acid in it, we see color formation in solution due to the resulting complex formed.
Question 2
The Fe(III) itself absorbs some light and gives an absorbance value for the solution. Therefore, it is necessary to blank the spectrophotometer with a Fe(III) solution prior to measurement of test solutions.
I don’t know really sorry
The mass percentage composition of nitrogen in CO(NH2)2 is 46 .7%
calculation
% mass = molar mass of nitrogen/ molar mass of Co(NH2)2
molar mass of nitrogen = 14 x2 = 28g/mol since there is two nitrogen atom in Co(NH2)2\
molar mass of CO(NH2)2 = 12 + 16 + (14 x2) +( 2 x2)= 60 g/mol
the % mass is therefore =28 / 60 x100 =46.7%
