A reversible process is a quasi-static process but a quasi-static process need not to be reversible, Explain?

Quasi-static Process:
An infinitely slow process such that the system undergoes changes in its variables (P,V,T) so slowly that it continues to be in its thermal, mechanical and chemical equilibrium with its surroundings all the time and at all points. (It is a hypothetical construct)
Or
A quasi static process is a process carried out very very slowly, in an attempt to reach as close as possible to a reversible process.
Or
A process in which two nearest state are always in equilibrium is called a quasi static process. This process takes place at an infinitesimal speed. 

Reversible Processes:
Any processing comprises of 2 states, initial and final. After the completion of any process ( initial to final ), if we go reverse ( final to initial ) and there is no change in the system or surrounding, then such a process is called reversible process.
Or
A process which is quasi-static and friction-less is called a reversible process. In fact, no actual occurring processes are reversible.

Reversible process is a quasi static process but a quasi static process need not to be reversible explain??
Reversible process is a slow process and it seems to be not moving as at every point of the process, Equilibrium is present!! So, As we know, at equilibrium the rate of forward reaction is equal to rate of backward reaction !!HENCE IT SEEMS TO BE STOPPED OR IN OTHER WORDS ,WE CAN NAME REVERSIBLE PROCESS AS A QUASI STATIC PROCESS!!
In order for any process to be reversible, it has to be infinitesimally close to thermal equilibrium. That makes it quasistatic by definition. However, any system that involves dissipation of energy as heat, whether by friction, vibration, or any other mechanism, cannot be reversible even if it is quasistatic. The canonical example is compression of a piston with friction between the piston and its containing cylinder. 

!!!THUS, THE PROCESS MAY BE QUASISTATIC IF IT IS CARRIED OUT VERY SLOWLY, BUT IT CAN NEVER BE A REVERSIBLE ONE IF THERE IS SOME OF THE COMPRESSIVE WORK IS LOST DUE TO FRICTION AND DISSIPATED AS HEAT!!!

☛ In general, there is not much difference between quasi static and reversible processes. Often these both are used alternative to each other. But in actual cases, quasi static processes without friction are termed as reversible. Because if friction exists, then entropy of the system increases, thereby makes the system irreversible.


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