Rohan and Alisha enter into a contract. A dispute arises and the arbitration clause says “any dispute shall be referred to one arbitrator mutually appointed by the parties”. Alisha unilaterally appoints her friend as arbitrator without informing Rohan, who gets to know mid-way through proceedings and issues directions. (1) Whether this appointment is valid under the Arbitration and Conciliation Act, 1996? (2) What options are available to Rohan to challenge this?