Dear Prakash,
Whenever you raise questions on employee's statutory rights or employer's statutory obligations, you should give complete information about the type of the establishment/industry, employee's capacity of employment like managerial, supervisory or workman, employment status like regular or out-sourced and in case of rights or benefits, whether they are statutory or flow from the contract of employment. Then only, you will get an appropriate answer.
Not all employees are eligible for leave encashment on termination of employment.
Not all kinds of leave are encashable on termination.
If leave encashment is statutory, no contract of employment can exclude it.