0.004 M solution of Na2SO4 is isotonic with 0.01M solution of glucose at same temperature. The approximate degree of dissociation of Na2SO4 is

For isotonic solutions                               i1C1 = i2C2Na2SO4                               Glucosei1 = ?                                      i2 = 1C1 = 0.004M                            C2 = 0.01M                      i1C1 = i2C2                          i1 (0.004) = i2(0.01)                 i1  = 2.5Na2SO4⇌2Na+ +SO4-2n=3i = 1+α(3-1)2.5 = 1+2αα=1.52=0.75