What is identity?

What is identical of SI unit of force constant?

What is the identity element with respect to multiplication?

What is the identity element with respect to subtraction in integers ?

Let S be the set of all 2xx2 matrices. What is the identity element of the multiplication operation on S?

Show that the table gives a commutative binary composition '*' on the set A = (a,b,c). What is the identity element?

An alkyl chloride produces a single alkene when it reacts with sodium ethoxide and ethanol . This alkene on hydrogenation produces 2-Methylbutane. What is the identity of the alkyl halide ?

A 12.0 M acid solution that contains 75.0% acid by mass has a density of 1.57g//mL . What is the identity of the acid?