What is identity?

What is the identity element with respect to multiplication?

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?

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 single alkene is produced when an alkyl bromide reacts with sodium ethoxide and ethanol. This alkene undergeoes hydrogenation and produces 2 - methyl butane . What is the identity of the alkyl bromide ?

What is the multiplicative identity of rational number?