At what temperature will the rms speed of oxygen molecule will be sufficient for escaping from the earth? ve=11.2  km  s−1,  mass  of   oxygen  molecule=2.76×10−26  kg  and  k=1.38×10−23J  k−1

Let the temperature be T.According to kinetic theory of gases, translational  KE=32kTThe oxygen molecule will escape from earth if,  32kT>12mve2i.e.,  T>mve23k  or  T>2.76×10−26×(11.2×103)23×1.38×10−23T>8.36×104K.