4% CH3COOH4 \% \mathrm{\ CH}_{3} \mathrm{COOH}4% CH3COOH
5% CH3COOH5 \% \mathrm{\ CH}_{3} \mathrm{COOH}5% CH3COOH
4% NaHCO34 \% \mathrm{\ NaHCO}_{3}4% NaHCO3
H3BO3\mathrm{H}_{3} \mathrm{BO}_{3}H3BO3