Question

Identify each of the following as acid or base.

a. ${\mathrm{H}}_2{\mathrm{SO}}_4$

b. $\mathrm{RbOH}$

c.$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$

d.$\mathrm{HI}$

Short answer

a. It is an acid.

b. It is a base.

c. It is a base.

d. It is an acid.

Step-by-step solution

Part (a) Given information

The given species is${\mathrm{H}}_2{\mathrm{SO}}_4$.

Part (a) Explanation

Acids are substances that are capable of donating a proton to another substance while bases are substances that accept a proton from an acid.

${\mathrm{H}}_2{\mathrm{SO}}_4$is a sulfuric acid, that is capable of donating a proton to another substance, and on dissociation, it produces a proton.

The dissociation of sulfuric acid can be given as:

${\mathrm{H}}_2{\mathrm{SO}}_4\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{{\mathrm{HSO}}_4}^{-}\left(\mathrm{aq}\right)$

Thus, it is an acid.

Part (b) Given information

The given substance is$\mathrm{RbOH}$.

Part (b) Explanation

Acids are substances that are capable of donating a proton to another substance while bases are substances that accept a proton from an acid.

$\mathrm{RbOH}$is Rubidium hydroxide, on dissociation it produces rubidium and hydroxide ions which confirms that it is a base.

The dissociation of rubidium hydroxide can be given as:

$\mathrm{RbOH}\left(\mathrm{aq}\right)\to {\mathrm{Rb}}^{+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$

Therefore, it is a base.

part (c) Given information

The given substance is$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$.

Part (c) Explanation

Acids are substances that are capable of donating a proton to another substance while bases are substances that accept a proton from an acid.

$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$is Calcium hydroxide, on dissociation it produces calcium and hydroxide ions which confirms that it is a base.

The dissociation of calcium hydroxide can be given as:

$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\left(\mathrm{aq}\right)\to {\mathrm{Ca}}^{2+}\left(\mathrm{aq}\right)+{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)$

Therefore, it is a base.

Part (d) Given information

The given substance is$\mathrm{HI}$.

Part (d) Explanation

Acids are substances that are capable of donating a proton to another substance while bases are substances that accept a proton from an acid.

$\mathrm{HI}$is Hydrogen iodide, which is capable of donating a proton to another substance, and on dissociation, it produces a proton.

The dissociation of hydrogen iodide is given as follows:

$\mathrm{HI}\left(\mathrm{aq}\right)\rightleftharpoons {\mathrm{H}}^{+}\left(\mathrm{aq}\right)+{\mathrm{I}}^{-}\left(\mathrm{aq}\right)$

Therefore, it is an acid.