6. The equilibrium constant for the reaction of MnO4- and Fe2+ is ( ) (E0 (MnO4-/Mn2+)= 1.51 V; E0 (Fe3+/Fe2+)=0.77V ) A. 320 B 3.41012 C 5.2 1062 D 4.81063 7. The end point indicator used in the Fajans Method is fluoroscein. It is an____ indicator ( B ). A. complexometric B. adsorption C. acid-base D. none of these 8. Which of the following has four significant figures? ( ) A[H+] = 0.0008 mol . L-1 B. pH =10.15 Cw(MgO) =12.47% D. 4000.0 9. Which of the following could be used as the primary standard? ( ) A. HCl B. NaOH C. KMnO4 D. K2Cr2O7 10. Which of the following statements is true? ( ) A Precise values may be inaccurate B Determinate errors can be constant or proportional C The variance is the square of the standard deviation D All of the above

please ans only the mcq no explanation needed.