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Exercises on acids, salts and bases
\[\require{mhchem}\]
Worked Exercises
Identify the following chemical species as Bronsted-Lowry acid or base:
a. \(\ce{HF}\)
b. \(\ce{PO}_{4}^{3-}\)
Answers
a. A Bronsted-Lowry acid as it contains hydrogen that can be donated as \(\ce{H}^{+}\).
b. The phosphate ion does not contain hydrogen. However, oxygen atoms present in the phosphate ion have lone pairs of electrons which can be shared with a proton/protons or a hydrogen ion/ions. Therefore, the phosphate ion is a Bronsted-Lowry base.
Write the formula for:
-
the conjugate base of \(\ce{H}_{3}\ce{PO}_{4}\) ,
-
the conjugate acid of \(\ce{NO}_{3}^{-}\).
Answers
After donating one hydrogen ion, \(\ce{H}_{3}\ce{PO}_{4}\) becomes \(\ce{H}_{2}\ce{PO}_{4}^{-}\). Therefore, the conjugate base of \(\ce{H}_{3}\ce{PO}_{4}\) is the \(\ce{H}_{2}\ce{PO}_{4}^{-}\) ion.
As a base \(\ce{NO}_{3}^{-}\) accepts a proton from an acid and becomes \(\ce{HNO}_{3}\). Therefore, the conjugate acid of \(\ce{NO}_{3}^{-}\) is the \(\ce{HNO}_{3}\).
1. \[ \ce{H}_{3}\ce{PO}_{4}\rightarrow\ce{H}^{+}+\ce{H}_{2}\ce{PO}_{4}^{-} \]
2. \[ \ce{NO}_{3}^{-}+\ce{H}^{+}\rightarrow\ce{HNO}_{3} \]
Exercises
Identify the following chemical species as a Bronsted-Lowry acid or base:
\(\ce{HClO}_{4}\)
Acid
\(\ce{HCOOH}\)
Acid
\(\ce{CN}^{-}\)
Base
\(\ce{SO}_{3}^{2-}\)
Base
\(\ce{H}_{2}\ce{S}\)
Acid
Write the chemical formulas for each of the following:
The conjugate acid of \(\ce{HS}^{-}\)
\(\ce{H}_{2}\ce{S}\)
The conjugate base of \(\ce{NH}_{4}^{+}\)
\(\ce{NH}_{3}\)
The conjugate acid of \(\ce{PO}_{4}^{3-}\)
\(\ce{HPO}_{4}^{2-}\)
The conjugate acid of \(\ce{HC}_{2}\ce{O}_{4}^{-}\)
\(\ce{H}_{2}\ce{C}_{2}\ce{O}_{4}\)
The conjugate base of \(\ce{H}_{2}\ce{CO}_{3}\)
\(\ce{HCO}_{3}^{-}\)