Overcoming hostility from a senior PhD student I am a Ph.D. third year student. In our college for most of the work we have to depend on our seniors as our advisor rarely takes interest in our research. My senior is always rude to me, and never supports me in anything. Sometimes she doesn't talk to me for a whole day, and even sometimes she misguides me. I feel so low. It becomes so difficult to be in a lab where only two people are working and not even talking to each other properly. How can I deal with this?
A friend was in a similar situation during her PhD.


  I am a Ph.D. third year student. In our college for most of the work
  we have to depend on our seniors as our advisor rarely takes interest
  in our research. 


There is really only one bright side to this situation: you will have to become a self-motivated and independent researcher quickly. Even if your advisor does not 'take interest' in your research make sure to meet with them regularly to discuss what you have done and what you are planning to do. This keeps them in the loop and aware of your efforts. To get additional input, you can contact other faculty in and outside your institute to get ideas or feedback on what you are doing. Former students from the same lab are also a good resource.


  My senior is always rude to me, and never supports me
  in anything. Sometimes she doesn't talk to me for a whole day, and


As @Dawn pointed out, your senior clearly does not want to be friends. The best you can do is be cordial in person, and keep all important communication over email. 


  even sometimes she misguides me.


Attributing this to ignorance, rather than malice, is the most productive solution here. You can take her suggestions/answers/advice but make sure to use your own judgement to verify this - whether from other students/researchers, literature, simulation, etc. This will also help you become a better researcher. 


  I feel so low. It becomes so
  difficult to be in a lab where only two people are working and not
  even talking to each other properly. How can I deal with this?


Treat the lab as your workplace. I have seen labs/groups that feel like family, and others that are unbelievably toxic. Focus on finishing your degree and moving on. Ensure that you maintain a social life with family/friends outside your lab, and get lots of fresh air and exercise.