Question

the chemical formulae of some acids are listed in the first column of the table below, and in the second column it says whether each acid is strong or weak. complete the table. list the chemical formula of each species present at concentrations greater than about 10^-6 mol/l when about a tenth of a mole of the acid is dissolved in a liter of water. acid strong or weak? species present at 10^-6 mol/l or greater when dissolved in water hbro4 strong hf weak hi strong h2co3 weak

Explanation:

Step1: Analyze strong acid \(HBrO_4\)

Strong acids dissociate completely in water. The dissociation reaction of \(HBrO_4\) is \(HBrO_4(aq)\to H^{+}(aq)+BrO_4^{-}(aq)\). So the species present at \(10^{-6}\text{ mol/L}\) or greater are \(H^{+}\) and \(BrO_4^{-}\).

Step2: Analyze weak acid \(HF\)

Weak acids do not dissociate completely. The dissociation reaction of \(HF\) is \(HF(aq)
ightleftharpoons H^{+}(aq)+F^{-}(aq)\). Also, water auto - ionizes \(H_2O(l)
ightleftharpoons H^{+}(aq)+OH^{-}(aq)\), but since \(HF\) is an acid, \(H^{+}\) from \(HF\) suppresses the ionization of water. The main species are \(HF\), \(H^{+}\), \(F^{-}\).

Step3: Analyze strong acid \(HI\)

Strong acids dissociate completely. The dissociation reaction of \(HI\) is \(HI(aq)\to H^{+}(aq)+I^{-}(aq)\). So the species present at \(10^{-6}\text{ mol/L}\) or greater are \(H^{+}\) and \(I^{-}\).

Step4: Analyze weak acid \(H_2CO_3\)

Weak acids do not dissociate completely. The first - step dissociation of \(H_2CO_3\) is \(H_2CO_3(aq)
ightleftharpoons H^{+}(aq)+HCO_3^{-}(aq)\), and the second - step dissociation \(HCO_3^{-}(aq)
ightleftharpoons H^{+}(aq)+CO_3^{2 -}(aq)\) is much weaker. Also, considering the presence of the undissociated \(H_2CO_3\) itself. The main species are \(H_2CO_3\), \(H^{+}\), \(HCO_3^{-}\).

Answer:

acid	strong or weak?	species present at \(10^{-6}\text{ mol/L}\) or greater when dissolved in water
\(HF\)	weak	\(HF,H^{+},F^{-}\)
\(HI\)	strong	\(H^{+},I^{-}\)
\(H_2CO_3\)	weak	\(H_2CO_3,H^{+},HCO_3^{-}\)