A solution of NaOH had a concentration of 20 g/dm3 What mass of NaOH would there be in 250 cm3 of the solution?

Iwould you figure it out but you don't have a picture or in your question as to what the physical property you're looking for is

Ais your answer to this

Answerd. may include all of these are many definitions of bases: the  brønsted-lowry definition of acids and bases says that bases are proton acceptors.the arrhenius definition of acids and bases says that bases increase [oh⁻] in solution (thereby producing oh⁻ ions)the lewis definition of acids and bases says that bases donate electron pairs.therefore, the sensible answer is that a base may include all of the described characteristics.