Reference Tables

Solubility Table for Acids, Bases, and Salts (\(20\,{}^{\circ}\text{C}\))

	\(\ce{OH-}\)	\(\ce{NO3-}\)	\(\ce{Cl-}\)	\(\ce{SO4^{2-}}\)	\(\ce{CO3^{2-}}\)	\(\ce{SiO3^{2-}}\)	\(\ce{PO4^{3-}}\)	\(\ce{S^{2-}}\)
\(\ce{H+}\)	—	Sol./Vol.	Sol./Vol.	Sol.	Sol./Vol.	Insol.	Sol.	Sol./Vol.
\(\ce{K+}\)	Sol.	Sol.	Sol.	Sol.	Sol.	Sol.	Sol.	Sol.
\(\ce{Na+}\)	Sol.	Sol.	Sol.	Sol.	Sol.	Sol.	Sol.	Sol.
\(\ce{NH4+}\)	Sol./Vol.	Sol.	Sol.	Sol.	Sol.	—	Sol.	Sol.
\(\ce{Ba^{2+}}\)	Sol.	Sol.	Sol.	Insol.	Insol.	Insol.	Insol.	Sol.
\(\ce{Ca^{2+}}\)	Sl.	Sol.	Sol.	Sl.	Insol.	Insol.	Insol.	Sl.
\(\ce{Mg^{2+}}\)	Insol.	Sol.	Sol.	Sol.	Sl.	Insol.	Insol.	—
\(\ce{Al^{3+}}\)	Insol.	Sol.	Sol.	Sol.	—	Insol.	Insol.	—
\(\ce{Zn^{2+}}\)	Insol.	Sol.	Sol.	Sol.	Insol.	Insol.	Insol.	Insol.
\(\ce{Fe^{2+}}\)	Insol.	Sol.	Sol.	Sol.	Insol.	Insol.	Insol.	Insol.
\(\ce{Fe^{3+}}\)	Insol.	Sol.	Sol.	Sol.	—	—	Insol.	—
\(\ce{Cu^{2+}}\)	Insol.	Sol.	Sol.	Sol.	Insol.	Insol.	Insol.	Insol.
\(\ce{Ag+}\)	—	Sol.	Insol.	Sl.	Insol.	—	Insol.	Insol.
\(\ce{Pb^{2+}}\)	Insol.	Sol.	Sl.	Insol.	Insol.	Insol.	Insol.	Insol.

Legend: “Sol.” = soluble in water; “Insol.” = insoluble in water; “Sl.” = slightly soluble in water; “Vol.” = volatile; “—” = the substance does not exist or decomposes upon contact with water.

Common Acid–Base Indicators

Indicator	Color in acidic solution	Color change range (pH)	Color in basic solution
Methyl orange	Red	3.1–4.4	Yellow
Litmus	Red	5.0–8.0	Blue
Phenolphthalein	Colorless	8.2–10.0	Red (pink)

Relative Strengths of Common Weak Electrolytes

Electrolyte	Ionization equilibrium	Ionization constant (\(25\,{}^{\circ}\text{C}\))
Acetic acid (\(\ce{CH3COOH}\))	\(\ce{CH3COOH <=> CH3COO- + H+}\)	\(K_a = 1.75 \times 10^{-5}\)
Carbonic acid (\(\ce{H2CO3}\))	\(\ce{H2CO3 <=> HCO3- + H+}\)	\(K_{a1} = 4.3 \times 10^{-7}\)
	\(\ce{HCO3- <=> CO3^{2-} + H+}\)	\(K_{a2} = 5.6 \times 10^{-11}\)
Phosphoric acid (\(\ce{H3PO4}\))	\(\ce{H3PO4 <=> H2PO4- + H+}\)	\(K_{a1} = 7.5 \times 10^{-3}\)
	\(\ce{H2PO4- <=> HPO4^{2-} + H+}\)	\(K_{a2} = 6.2 \times 10^{-8}\)
	\(\ce{HPO4^{2-} <=> PO4^{3-} + H+}\)	\(K_{a3} = 2.2 \times 10^{-13}\)
Hydrofluoric acid (\(\ce{HF}\))	\(\ce{HF <=> F- + H+}\)	\(K_a = 3.5 \times 10^{-4}\)
Nitrous acid (\(\ce{HNO2}\))	\(\ce{HNO2 <=> NO2- + H+}\)	\(K_a = 4.5 \times 10^{-4}\)
Hydrocyanic acid (\(\ce{HCN}\))	\(\ce{HCN <=> CN- + H+}\)	\(K_a = 4.9 \times 10^{-10}\)
Ammonia (\(\ce{NH3 . H2O}\))	\(\ce{NH3 . H2O <=> NH4+ + OH-}\)	\(K_b = 1.8 \times 10^{-5}\)

Standard Electrode Potentials (Selected, \(25\,{}^{\circ}\text{C}\))

Half-reaction	\(E^{\circ}\) (V)
\(\ce{K+ + e- -> K}\)	\(-2.924\)
\(\ce{Ca^{2+} + 2e- -> Ca}\)	\(-2.866\)
\(\ce{Na+ + e- -> Na}\)	\(-2.714\)
\(\ce{Mg^{2+} + 2e- -> Mg}\)	\(-2.372\)
\(\ce{Al^{3+} + 3e- -> Al}\)	\(-1.662\)
\(\ce{Zn^{2+} + 2e- -> Zn}\)	\(-0.762\)
\(\ce{Fe^{2+} + 2e- -> Fe}\)	\(-0.447\)
\(\ce{Ni^{2+} + 2e- -> Ni}\)	\(-0.257\)
\(\ce{Sn^{2+} + 2e- -> Sn}\)	\(-0.138\)
\(\ce{Pb^{2+} + 2e- -> Pb}\)	\(-0.126\)
\(\ce{2H+ + 2e- -> H2}\)	\(0.000\)
\(\ce{Cu^{2+} + 2e- -> Cu}\)	\(+0.342\)
\(\ce{Ag+ + e- -> Ag}\)	\(+0.799\)
\(\ce{Hg^{2+} + 2e- -> Hg}\)	\(+0.851\)
\(\ce{Pt^{2+} + 2e- -> Pt}\)	\(+1.188\)
\(\ce{Au^{3+} + 3e- -> Au}\)	\(+1.498\)