Which of the following is a property of a pure substance?
it consists of different types of compounds.
it may have substances in different states of matter.
the ratio of the particles that make it up is fixed.
its components can be separated by employing physical methods.

a saline water is fed to a reverse osmosis unit at flow rate o rotameter connected to reject (retentate) line reads 8 installed in reject and permeate line reads 15.2 milli siemens/cm and 300 micro siemens/com respectively.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.