Monosodium citrate, or sodium dihydrogen citrate, is one of the 3 citric acid salts with the chemical formula NaH2C6H5O7. It is commonly used as a relatively strong sequestrant due to the 2 labile hydrogen atoms on the citrate molecule.
Monosodium citrate can be prepared by 1 step reaction between sodium carbonate or bicarbonate and citric acid:
NaHCO3 (s) + C6H8O7 (aq) → NaC6H7O7 (aq) + CO2 (g) + H2O (l).
It is often used as a food preservative and as a flavouring in the food industry. Mono sodium citrate imparts a cool and saline taste to beverages. It also acts as a buffer together with free acid in beverages and jellies.
In the pharmaceutical industry, it is used to control pH. It may be used as an alkalizing agent, buffering agent, emulsifier, or as a strong sequestering agent. Mono sodium citrate is also used as an anticoagulant in donated blood.