4% NaHCO34 \% \mathrm{\ NaHCO}_{3}4% NaHCO3
4% NaOH4 \% \mathrm{\ NaOH}4% NaOH
4% Ca(OH)24 \% \mathrm{\ Ca}(\mathrm{OH})_{2}4% Ca(OH)2
4% Mg(OH)24 \% \mathrm{\ Mg}(\mathrm{OH})_{2}4% Mg(OH)2
