Let the n-factor of KMnO4​ in acid, neutral and alkaline media are N1​,N2​ and N3​ respectively. Also, the same volumes of reducing agent are used every time, same number of equivalents of KMnO4​ would be required every time.⇒20N1​=3100​N2​=100N3​⇒N1​=35​N2​=5N3​Also, n-factors are all integer and greater than or equal to one but less than six, N3​ must be 1 .⇒N1​=5,N2​=3∴ In acid medium MnO4−​⟶Mn2+In neutral medium MnO4−​⟶Mn4+In alkaline medium MnO4−​⟶Mn6+⇒⇒⇒​ meq of K2​Cr2​O7​ required =100100=1×6×V(n-factor =6)V=100/6=16.67 mL​