Toothpaste is an abrasive that contains many things, but mainly phosphates.
Yes, refer to the previous answer.
Answer:
As nouns the difference between impression and imprint
is that impression is the indentation or depression made by the pressure of one object on or into another while imprint is an impression; the mark left behind by printing something.
Explanation:
As per Brønsted-Lowry concept of acids and bases, chemical species which donate proton are called Brønsted-Lowry acids.
The chemical species which accept proton are called Brønsted-Lowry base.
(a) 
is Bronsted lowry acid and
is its conjugate base.
is Bronsted lowry base and
is its conjugate acid.
(b)

is Bronsted lowry base and HCN is its conjugate acid.
is Bronsted lowry acid and
is its conjugate base.
(c)

is Bronsted lowry acid and
is its conjugate base.
Cl^- is Bronsted lowry base and HCl is its conjugate acid.
(d)

is Bronsted lowry acid and
is its conjugate base.
OH^- is Bronsted lowry base and
is its conjugate acid.
(e)

is Bronsted lowry base and OH- is its conjugate acid.
is Bronsted lowry acid and OH- is its conjugate base.