碳酸氢钠的化学性质,质量标准及用途

化学性质

白色结晶性粉末或颗粒。溶于水，几乎不溶于乙醇，约在50℃失去二氧化碳，热在100℃全部变为碳酸钠。在弱酸中迅速分解，其水溶液在20℃时开始分解出二氧化碳和碳酸钠，到沸点时全部分解。25℃时溶于10份水，约18℃时溶于12份水，其冷水制成的没有搅动的溶液，对酚酞试纸鲜配制的0.1mol/L水溶液pH值8.3。低毒，半数致死量(大鼠，经口)4420mg/kg。
密度：2.159
熔点：270 °C

质量标准

  AR
项目                                                                        优级纯          分析纯       化学纯 
                                                                                (GR)             (AR)       ( CP)

含量(NaHCO3)Assay,%                                     ≥99.8       99.8      99.8   
水溶液反应water Solution
reaction                                                                合格          合格        合格
澄清度试验Clarity                                               合格          合格          合格       
水不溶物Insiluble matter in water,%             ≤0.005      0.01      0.02
氯化物及氯酸盐(以Cl计)
Chloride and chlorate,%                                 ≤0.001      0.002     0.005
硫化合物(以SO4计)Sulur
compounds,%                                                 ≤0.002      0.005     0.01   
氮化合物(N)Nitrogen,%                                 ≤0.0005     0.001     0.002 
磷酸盐(以PO4计)Phosphate,%                    ≤0.001      0.002     0.005
硅酸盐(以SiO3计)Silicate,%                         ≤0.001      0.005     0.01
镁(Mg)Magnesium,%                                     ≤0.002      0.003     0.005 
钾(K）Potassium,%　                                  ≤0.005      0.01       0.02  
铝(Al)Aluminum,%                                         ≤0.005      0.01        0.02 
钙(Ca)Calcium,%                                           ≤0.005      0.007     0.001  
铁(Fe)Iron,%                                                   ≤0.0005     0.001     0.002 
重金属(以Pb计)Heavy metals,%                  ≤0.0005     0.001     0.002  
还原碘物质(以HCOOH计)                            ≤0.005        --       --    
Substances reducing iodine

ACS级
项目名称　                                            ACS Grade
含量(NaHCO3)Assay                          99.7-100.3%
水不溶物Insoluble matter                  ≤0.015%
总氮量(以Cl计)Total chlorine            ≤0.003%
磷酸盐(PO4)Phosphate                    ≤0.003%
铵(NH4)Ammonium                           ≤5ppm
重金属(以Pb计)Heavy metals          ≤5ppm
铁(Fe)Iron                                            ≤0.001%
钙(Ca)Calcium                                  ≤0.02%
镁(Mg)Magnesium                            ≤0.005%
钾(K)Potassium                                ≤0.005%