In a distributed system several devices are connected to each other to share resources like software's or hardware's, which makes Mutual Exclusion essential for distributed system during the sharing process. The region where all the sharing takes place is the Critical region. Mutual Exclusion on Distributed system allows critical resource to be shared between different mobile nodes in a Mobile Ad-Hoc Network. In this the region is divided and in a logical way sharing is done. Critical section can be defined as a state when a node or device is actually sharing or using the resources which are required in the process of communicating with each other. A request is involved for making decision regarding that which node or device would enter critical section. This request can be made to neighboring nodes or by imposing any algorithm which can make it possible the sharing process to be fair for each node i.e. no node should wait for an infinite time for its turn or no node should get infinite access to resources. In this paper, several mutual exclusion algorithms are discussed by comparing their advantages and disadvantages. Section 1 includes the introduction of the Distributed Mutual Exclusion problem and its categories. In Section 2 the basic requirements for a system to attain mutual exclusion. In section 3 discussions of all the algorithms is covered.