Is friction a conservative force? Give reason.

No, friction is not a conservative force.
Reason:
A conservative force is one for which the work done in moving an object between two points depends only on the initial and final positions, and not on the path taken. In addition, the work done by a conservative force in a closed loop (where the object returns to its original position) is zero.
However, friction does not satisfy these conditions:
1. Path Dependence: The work done by friction depends on the path taken. For example, if an object moves along a curved path or a straight path, the frictional force will do different amounts of work in each case, even if the initial and final positions are the same.
2. Non-zero Work in a Closed Loop: If an object moves in a closed loop and returns to its original position, the work done by friction will not be zero. Instead, friction always does negative work (removes energy) as it opposes the motion. Hence, when an object returns to its starting point, the energy lost due to friction is not recovered.
Since the work done by friction does depend on the path and does not return to zero in a closed loop, friction is not a conservative force.