<prompt> Which of the following local anaesthetic should not be alkalinized with soda bicarbonateLignocaineProcaineBupivacaineBenzocaine  <response>: Local anaesthetic drug if dissociated it wont act on sodium channel.So drug is kept undissociated by adding soda bicarbonate to maintain pka 7.7 8.2But for bupivacaine soda bicarbonate is not used as it gets precipitated. 