Please answer all the 4 sub question

13 A 20.0 mL aliquot of a solution containing 10.0 g/L of a mixture of Fe{ll) and Fe(ill) was titrated with 13.10 mL of 0.03 M K2Cr207 solution. The concentration of Fell in the sample is OS (4 Points) 98 g/L 11.0 g/L. 3.4 g/L 66 g/L. 43 g/L 12 A 10.00 ml sample containing 8.00 g/L of a mixture of KCl and NaCl was titrated with 0.10 M standard solution of AgNO3, where 5.6 mL was needed to reach the end-point. Calculate the mass of sample (in grams). (3.5 points) 0.0800 010083 0:0337 0.0033 0.0221 14 Concerning EDTA titrations, which of the following is correct? (3.5 Points) EDTA forms 12 complexes with metal ions. The most widely used indicators are murexide and Eriochrome Black T. In presence of NaOH, EDTA reacts only with Mg+2 tons, using murexide indicator The water hardness is usually expressed as MgCO3 mg/L water. EDTA solution was standardized using Nag 15 If 30.0 mL of EDTA solution is required to titrate 45.0 mL of 0.05 M solution of Zn2. the molar concentration of the EDTA solution is: (3.5 Points) 0.150 M 0.660 M 0,075 M 0.050 M 1.038 M