Question

Rank these systems in order of decreasing entropy.

Rank from highest to lowest entropy. To rank items as equivalent, overlap them.
a process run infinitesimally slowly at equilibrium and reversed to its original statea constant composition mixture of solid and liquid water at STP (273.15 K and 1 atm)motion of a frictionless pendulumtitration of sodium hydroxide and hydrochloric acidice melting to water above the melting pointhydrogen peroxide slowly decomposing into water and oxygen

Answer 1

High entropy means higher degree of irreversibility
Negative entropy means that the process is reversible
The order of the system in decreasing entropy is

sodium hydroxide and hydrochloric acid
hydrogen peroxide slowly decomposing into water and oxygen
motion of a frictionless pendulum
a constant composition mixture of solid and liquid water at STP (273.15 K and 1 atm)
a process run infinitesimally slowly at equilibrium and reversed to its original state